Address Review of the Reworked Unit Tests

Recompute the v4 recipe comparison once instead of per feature (148 s to 6 s) and compare bounding boxes as well as volumes; drop the incidental NaN loop from the unrepairable Voronoi case; prove the renamed preset is the one selected instead of checking a dirty flag that selecting clears; tell sparse from empty infill in the solid-shell test; plus smaller cleanups.

src/slic3r/plugin/PythonInterpreter.cpp

@@ -584,6 +584,19 @@ bool PythonInterpreter::initialize()
         }
         BOOST_LOG_TRIVIAL(debug) << "Program name set successfully";
 
+        // Keep bytecode out of the Python home. The shipped .pyc files are stale against their
+        // sources, so a writable install would rewrite them inside the app (breaking a signed
+        // macOS bundle's seal) and a read-only one would recompile them on every launch.
+        const std::string pycache_prefix = data_dir() + "/python/pycache";
+#ifdef _WIN32
+        status = PyConfig_SetString(&config, &config.pycache_prefix, boost::nowide::widen(pycache_prefix).c_str());
+#else
+        status = PyConfig_SetBytesString(&config, &config.pycache_prefix, pycache_prefix.c_str());
+#endif
+        if (PyStatus_Exception(status))
+            BOOST_LOG_TRIVIAL(warning) << "Failed to set the Python bytecode cache to " << pycache_prefix << ": "
+                                       << (status.err_msg ? status.err_msg : "unknown error");
+
         // Use pybind11's scoped_interpreter which properly initializes
         // pybind11 internals for multi-threaded use — raw Py_InitializeFromConfig
         // does not set up thread state tracking that pybind11 requires.

tests/fff_print/test_cooling.cpp

@@ -1,6 +1,7 @@
 #include <catch2/catch_all.hpp>
 
 #include <catch2/catch_test_macros.hpp>
+#include <catch2/catch_message.hpp>
 #include "test_helpers.hpp"
 
 #include <algorithm>
@@ -17,15 +18,48 @@
 using namespace Slic3r;
 using namespace Slic3r::Test;
 
-// The fan is held off for the first close_fan_the_first_x_layers layers, so an explicit
-// fan-off command is emitted.
+// The fan stays off while printing the first close_fan_the_first_x_layers layers and runs afterwards.
 TEST_CASE("Fan is held off for the initial layers", "[Cooling]")
 {
+    const int fan_off_layers = 5;
     const std::string gcode = slice({ cube(20) }, {
-        { "cooling",                      true },
-        { "close_fan_the_first_x_layers", 5 },
+        { "close_fan_the_first_x_layers", fan_off_layers },
+        { "full_fan_speed_layer",         0 },
+        { "fan_min_speed",                50 },
+        { "fan_max_speed",                100 },
+        { "fan_cooling_layer_time",       1000 }, // every layer is short enough to run the fan
+        { "layer_height",                 0.2 },
+        { "initial_layer_print_height",   0.2 },
     });
-    CHECK(gcode.find("M106 S0") != std::string::npos);
+
+    // Record, for each layer, whether any extrusion was printed with the part fan running.
+    std::vector<bool> extruded_with_fan;
+    int  layer    = -1;
+    bool fan_on   = false;
+    std::istringstream input(gcode);
+    std::string line;
+    while (std::getline(input, line)) {
+        if (line.rfind(";LAYER_CHANGE", 0) == 0) {
+            ++layer;
+            extruded_with_fan.push_back(false);
+        } else if (line.rfind("M107", 0) == 0) {
+            fan_on = false;
+        } else if (line.rfind("M106 ", 0) == 0 && line.find(" P") == std::string::npos) {
+            const size_t s = line.find(" S");
+            fan_on = s != std::string::npos && std::stod(line.substr(s + 2)) > 0.;
+        } else if (layer >= 0 && fan_on && line.rfind("G1 ", 0) == 0 && line.find(" E") != std::string::npos &&
+                   (line.find(" X") != std::string::npos || line.find(" Y") != std::string::npos)) {
+            extruded_with_fan[layer] = true;
+        }
+    }
+
+    // A 20 mm cube at 0.2 mm layers has 100 layers.
+    REQUIRE(extruded_with_fan.size() == 100);
+    for (int i = 0; i < fan_off_layers; ++i) {
+        CAPTURE(i);
+        CHECK_FALSE(extruded_with_fan[i]);
+    }
+    CHECK(extruded_with_fan[fan_off_layers]);
 }
 
 // The cooling pass resolves and strips its internal speed placeholders; none leak into

tests/fff_print/test_fill.cpp

@@ -86,10 +86,9 @@ TEST_CASE("Pattern path length", "[Fill]") {
             Slic3r::Polylines paths = test(Slic3r::ExPolygon(test_set));
             REQUIRE(paths.size() == 1); // one continuous path
 
-            // TODO: determine what the "Expected length" should be for rectilinear fill of a 100x100 polygon. 
-            // This check only checks that it's above scale(3*100 + 2*50) + scaled_epsilon.
-            // ok abs($paths->[0]->length - scale(3*100 + 2*50)) - scaled_epsilon, 'path has expected length';
-            REQUIRE(std::abs(paths[0].length() - static_cast<double>(scale_(3*100 + 2*50))) - SCALED_EPSILON > 0); // path has expected length
+            // Lines are 50 mm apart and the square is inset by half a spacing, so the lines on its edges drop out
+            // and a single line crosses the middle, ending within half a spacing of the edges.
+            CHECK_THAT(unscale<double>(paths[0].length()), Catch::Matchers::WithinAbs(100., filler->spacing / 2.));
 
             test_set.clear();
         }
@@ -148,10 +147,9 @@ TEST_CASE("Pattern path length", "[Fill]") {
         Slic3r::Polylines paths = test(Slic3r::ExPolygon(points));
         REQUIRE(paths.size() == 1); // one continuous path
 
-        // TODO: determine what the "Expected length" should be for rectilinear fill of a 100x100 polygon. 
-        // This check only checks that it's above scale(3*100 + 2*50) + scaled_epsilon.
-        // ok abs($paths->[0]->length - scale(3*100 + 2*50)) - scaled_epsilon, 'path has expected length';
-        REQUIRE(std::abs(paths[0].length() - static_cast<double>(scale_(3*100 + 2*50))) - SCALED_EPSILON > 0); // path has expected length
+        // A solid fill covers the area with lines one spacing apart, so a missing segment shortens the path.
+        const double expected_length = unscale<double>(unscale<double>(Slic3r::ExPolygon(points).area())) / filler->spacing;
+        CHECK_THAT(unscale<double>(paths[0].length()), Catch::Matchers::WithinRel(expected_length, 0.01));
     }
 
     SECTION("Rotated Square") {
@@ -168,8 +166,9 @@ TEST_CASE("Pattern path length", "[Fill]") {
 		fill_params.density = 1.0;
 		filler->spacing = flow.spacing();
 
-        for (auto angle : { 0.0, 45.0}) {
+        for (auto angle : { 0.0, PI / 4.0 }) {
             surface.expolygon.rotate(angle, Point(0,0));
+            filler->bounding_box = get_extents(surface.expolygon.contour);
             Polylines paths = filler->fill_surface(&surface, fill_params);
             REQUIRE(paths.size() == 1);
         }
@@ -222,7 +221,7 @@ TEST_CASE("Pattern path length", "[Fill]") {
         };
         Slic3r::ExPolygon expolygon(points);
          
-        REQUIRE(test_if_solid_surface_filled(expolygon, 0.5, 45.0, 0.99) == true);
+        REQUIRE(test_if_solid_surface_filled(expolygon, 0.5, PI / 4.0, 0.99) == true);
     }
 }
 

tests/fff_print/test_print.cpp

@@ -123,38 +123,58 @@ SCENARIO("Changing the number of solid shell layers does not make all surfaces i
 		config.set_deserialize_strict({
             { "top_shell_layers",           2 },
             { "bottom_shell_layers",        1 },
-            { "layer_height",               0.25 }, // get a known number of layers
+            // Shell counts alone decide which layers are solid.
+            { "top_shell_thickness",        0 },
+            { "bottom_shell_thickness",     0 },
+            { "sparse_infill_density",      "20%" },
+            { "layer_height",               0.25 }, // 80 layers: 0..79
             { "initial_layer_print_height", 0.25 }
 			});
         Slic3r::Print print;
         Slic3r::Model model;
         Slic3r::Test::init_print({cube(20)}, print, model, config);
-        // Precondition: Ensure that the model has 2 solid top layers (79, 78)
-        // and one solid bottom layer (0).
-		auto test_is_solid_infill = [&print](size_t obj_id, size_t layer_id) {
+        // True when the layer has fill surfaces and all of them are solid.
+		auto is_solid_infill = [&print](size_t obj_id, size_t layer_id) {
 		    const Layer &layer = *(print.objects().at(obj_id)->get_layer((int)layer_id));
-		    // iterate over all of the regions in the layer
-		    for (const LayerRegion *region : layer.regions()) {
-		        // for each region, iterate over the fill surfaces
+		    bool has_fill = false;
+		    for (const LayerRegion *region : layer.regions())
+		        for (const Surface &surface : region->fill_surfaces.surfaces) {
+		            if (! surface.is_solid())
+		                return false;
+		            has_fill = true;
+		        }
+		    return has_fill;
+		};
+        // True when the layer has a sparse fill surface, so a layer with no fill at all does not count.
+		auto has_sparse_infill = [&print](size_t obj_id, size_t layer_id) {
+		    const Layer &layer = *(print.objects().at(obj_id)->get_layer(static_cast<int>(layer_id)));
+		    for (const LayerRegion *region : layer.regions())
 		        for (const Surface &surface : region->fill_surfaces.surfaces)
-		            CHECK(surface.is_solid());
-		    }
+		            if (! surface.is_solid())
+		                return true;
+		    return false;
 		};
         print.process();
-        test_is_solid_infill(0,  0); // should be solid
-        test_is_solid_infill(0, 79); // should be solid
-        test_is_solid_infill(0, 78); // should be solid
+        // Precondition: 2 solid top layers (79, 78) and one solid bottom layer (0).
+        REQUIRE(is_solid_infill(0,  0));
+        REQUIRE(is_solid_infill(0, 79));
+        REQUIRE(is_solid_infill(0, 78));
+        REQUIRE(has_sparse_infill(0, 77));
         WHEN("Model is re-sliced with top_shell_layers == 3") {
 			config.set("top_shell_layers", 3);
 			print.apply(model, config);
             print.process();
             THEN("Print object does not have 0 solid bottom layers.") {
-                test_is_solid_infill(0, 0);
+                CHECK(is_solid_infill(0, 0));
             }
             AND_THEN("Print object has 3 top solid layers") {
-                test_is_solid_infill(0, 79);
-                test_is_solid_infill(0, 78);
-                test_is_solid_infill(0, 77);
+                CHECK(is_solid_infill(0, 79));
+                CHECK(is_solid_infill(0, 78));
+                CHECK(is_solid_infill(0, 77));
+                CHECK(has_sparse_infill(0, 76));
+            }
+            AND_THEN("Middle layers keep sparse infill") {
+                CHECK(has_sparse_infill(0, 40));
             }
         }
     }
@@ -672,14 +692,18 @@ TEST_CASE("gcode_skip_config_block omits the resolved-settings comment block", "
 {
     const std::string gcode = slice({ cube(20) }, {
         { "gcode_skip_config_block", true },
-        { "gcode_comments",         true },
     });
     CHECK(gcode.find("; CONFIG_BLOCK_START")     == std::string::npos);
     CHECK(gcode.find("; CONFIG_BLOCK_END")       == std::string::npos);
     CHECK(gcode.find("; layer_height =")         == std::string::npos);
-    CHECK(gcode.find("; fill_density =")         == std::string::npos);
+    CHECK(gcode.find("; sparse_infill_density =") == std::string::npos);
     CHECK(gcode.find("; HEADER_BLOCK_START")     != std::string::npos);
     CHECK(gcode.find("; EXECUTABLE_BLOCK_START") != std::string::npos);
+
+    const std::string with_block = slice({ cube(20) }, { { "gcode_skip_config_block", false } });
+    CHECK(with_block.find("; CONFIG_BLOCK_START")      != std::string::npos);
+    CHECK(with_block.find("; layer_height =")          != std::string::npos);
+    CHECK(with_block.find("; sparse_infill_density =") != std::string::npos);
 }
 
 // Some firmwares only scan the last N lines of the file for "estimated printing time", so it

tests/fff_print/test_trianglemesh.cpp

@@ -1,6 +1,8 @@
 #include <catch2/catch_all.hpp>
 
 #include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+#include <catch2/matchers/catch_matchers.hpp>
 #include "libslic3r/TriangleMesh.hpp"
 #include "libslic3r/TriangleMeshSlicer.hpp"
 #include "libslic3r/Point.hpp"
@@ -162,21 +164,29 @@ SCENARIO("Slice behavior", "[TriangleMesh]") {
         const std::vector<Vec3f> vertices {{0,0,0},{0,0,20},{0,5,0},{0,5,20},{50,0,0},{50,0,20},{15,5,0},{35,5,0},{15,20,0},{50,5,0},{35,20,0},{15,5,10},{50,5,20},{35,5,10},{35,20,10},{15,20,10}};
         const std::vector<Vec3i32> facets {{0,1,2},{2,1,3},{1,0,4},{5,1,4},{0,2,4},{4,2,6},{7,6,8},{4,6,7},{9,4,7},{7,8,10},{2,3,6},{11,3,12},{7,12,9},{13,12,7},{6,3,11},{11,12,13},{3,1,5},{12,3,5},{5,4,9},{12,5,9},{13,7,10},{14,13,10},{8,15,10},{10,15,14},{6,11,8},{8,11,15},{15,11,13},{14,15,13}};
 
-		auto cube = make_cube();
+		TriangleMesh mesh(vertices, facets);
+        // A 50x5x20 wall with a 20x15x10 block against it, so the block's top is at Z = 10.
+        const double wall_area       = 50. * 5.;
+        const double wall_block_area = wall_area + 20. * 15.;
+        const auto area_mm2 = [](const ExPolygons &slice) { return slice.at(0).area() * SCALING_FACTOR * SCALING_FACTOR; };
         WHEN(" a top tangent plane is sliced") {
-            // At Z = 10 we have a top horizontal surface.
-			std::vector<ExPolygons> slices = cube.slice({5.0, 10.0});
+			std::vector<ExPolygons> slices = mesh.slice({5.0, 10.0});
             THEN( "its area is included") {
-                REQUIRE(slices.at(0).at(0).area() > 0);
-                REQUIRE(slices.at(1).at(0).area() > 0);
+                REQUIRE(slices.at(0).size() == 1);
+                REQUIRE(slices.at(1).size() == 1);
+                CHECK_THAT(area_mm2(slices.at(0)), Catch::Matchers::WithinRel(wall_block_area, 1e-6));
+                CHECK_THAT(area_mm2(slices.at(1)), Catch::Matchers::WithinRel(wall_block_area, 1e-6));
             }
         }
         WHEN(" a model that has been transformed is sliced") {
-            cube.mirror_z();
-			std::vector<ExPolygons> slices = cube.slice({-5.0, -10.0});
-            THEN( "it is sliced properly (mirrored bottom plane area is included)") {
-                REQUIRE(slices.at(0).at(0).area() > 0);
-                REQUIRE(slices.at(1).at(0).area() > 0);
+            mesh.mirror_z();
+			std::vector<ExPolygons> slices = mesh.slice({-5.0, -10.0});
+            THEN( "it is sliced like the original, and the mirrored block's bottom plane is not part of it") {
+                REQUIRE(slices.at(0).size() == 1);
+                REQUIRE(slices.at(1).size() == 1);
+                CHECK_THAT(area_mm2(slices.at(0)), Catch::Matchers::WithinRel(wall_block_area, 1e-6));
+                // A triangle owns its top edge but not its bottom edge, so a bottom tangent plane is left out.
+                CHECK_THAT(area_mm2(slices.at(1)), Catch::Matchers::WithinRel(wall_area, 1e-6));
             }
         }
     }

tests/filament_group/filament_group_regression_main.cpp

@@ -319,9 +319,18 @@ TEST_CASE("FilamentGroup property checks", "[filament_group][property]") {
         // build (config_b/config_c cases evaluate the full per-layer nozzle-aware reorder for every
         // candidate grouping; this is a guard against hangs, not a micro-perf gate).
         REQUIRE(result.elapsed_ms < 40000.0);
-        REQUIRE(result.flush_cost >= 0);
 
+        // Every case, feasible or not, must yield a usable grouping: each used filament is
+        // assigned to an existing nozzle.
         auto used_filaments = collect_sorted_used_filaments(tc.context.model_info.layer_filaments);
+        const auto &nozzle_list = tc.context.nozzle_info.nozzle_list;
+        for (unsigned int fil : used_filaments) {
+            INFO("Filament: " << fil);
+            REQUIRE(fil < result.filament_map.size());
+            CHECK(result.filament_map[fil] >= 0);
+            CHECK(result.filament_map[fil] < static_cast<int>(nozzle_list.size()));
+        }
+
         if (is_constraint_feasible(tc.context, used_filaments)) {
             if (!result.constraints_ok) {
                 for (auto& v : result.violations)

tests/libslic3r/test_3mf.cpp

@@ -1033,18 +1033,19 @@ SCENARIO("Non-standard nozzle diameter survives .3mf save on a single-nozzle pri
     }
 }
 
-// A legacy / foreign project (no multi-nozzle metadata) must load crash-safe through the BBS
-// importer and must not fabricate a filament_volume_map.
-SCENARIO("Legacy project loads crash-safe via load_bbs_3mf", "[3mf][MultiNozzle]") {
-    GIVEN("a project without any multi-nozzle metadata") {
-        std::string path = std::string(TEST_DATA_DIR) + "/test_3mf/Geräte/Büchse.3mf";
-        Model                model;
-        DynamicPrintConfig   config;
-        ConfigSubstitutionContext ctxt{ ForwardCompatibilitySubstitutionRule::Enable };
-        PlateDataPtrs        plates;
-        std::vector<Preset*> project_presets;
-        bool   is_bbl_3mf = false, is_orca_3mf = false;
-        Semver file_version;
+// A project without multi-nozzle metadata must load through the BBS importer and must not
+// fabricate a filament_volume_map.
+SCENARIO("Projects without multi-nozzle metadata load without a per-filament volume map", "[3mf][MultiNozzle]") {
+    ConfigSubstitutionContext ctxt{ ForwardCompatibilitySubstitutionRule::Enable };
+    std::vector<Preset*>      project_presets;
+    bool   is_bbl_3mf = false, is_orca_3mf = false;
+    Semver file_version;
+
+    GIVEN("a legacy project with a bare model and no plate metadata") {
+        std::string        path = std::string(TEST_DATA_DIR) + "/test_3mf/Geräte/Büchse.3mf";
+        Model              model;
+        DynamicPrintConfig config;
+        PlateDataPtrs      plates;
 
         WHEN("loaded through the BBS importer") {
             bool loaded = false;
@@ -1052,10 +1053,32 @@ SCENARIO("Legacy project loads crash-safe via load_bbs_3mf", "[3mf][MultiNozzle]
                                                   &project_presets, &is_bbl_3mf, &is_orca_3mf,
                                                   &file_version, nullptr,
                                                   LoadStrategy::LoadModel | LoadStrategy::LoadConfig));
-            THEN("it does not crash and invents no per-filament volume map") {
-                for (PlateData* p : plates) {
-                    REQUIRE(p->config.option<ConfigOptionInts>("filament_volume_map") == nullptr);
-                }
+            THEN("the model loads") {
+                REQUIRE(loaded);
+                REQUIRE_FALSE(model.objects.empty());
+            }
+            release_PlateData_list(plates);
+        }
+    }
+
+    GIVEN("a project with plate metadata but no filament volume map") {
+        ScopedTemporaryFile temp(".3mf");
+        store_painted_cube(temp.string());
+        ScopedTemporaryDir backup_dir("orca_volume_map_dst");
+        Model              model;
+        model.set_backup_path(backup_dir.string());
+        DynamicPrintConfig config;
+        PlateDataPtrs      plates;
+
+        WHEN("loaded through the BBS importer") {
+            const bool loaded = load_bbs_3mf(temp.string().c_str(), &config, &ctxt, &model, &plates,
+                                             &project_presets, &is_bbl_3mf, &is_orca_3mf, &file_version,
+                                             nullptr, LoadStrategy::LoadModel | LoadStrategy::LoadConfig);
+            THEN("every plate loads without a per-filament volume map") {
+                REQUIRE(loaded);
+                REQUIRE_FALSE(plates.empty());
+                for (PlateData* p : plates)
+                    CHECK(p->config.option<ConfigOptionInts>("filament_volume_map") == nullptr);
             }
             release_PlateData_list(plates);
         }
@@ -2026,8 +2049,8 @@ SCENARIO("Published 3MF round-trips the extended material metadata", "[3mf]") {
                 REQUIRE(dst_model.model_info != nullptr);
                 REQUIRE(dst_model.model_info->metadata_items[ORCA_PUBLISHED_MATERIAL_TAG] == material_keys_json);
 
-                // The value must parse back with every extended field intact.
-                nlohmann::json entries = nlohmann::json::parse(material_keys_json);
+                // The loaded value must parse back with every extended field intact.
+                nlohmann::json entries = nlohmann::json::parse(dst_model.model_info->metadata_items[ORCA_PUBLISHED_MATERIAL_TAG]);
                 REQUIRE(entries.is_array());
                 REQUIRE(entries.size() == 1);
                 REQUIRE(entries[0]["full"].get<bool>() == true);

tests/libslic3r/test_caddocument.cpp

@@ -44,6 +44,7 @@
 
 #include <cmath>
 #include <cstring>
+#include <boost/filesystem/path.hpp>
 #include <fstream>
 #include <memory>
 #include <set>
@@ -53,6 +54,7 @@
 #include <BRepAdaptor_Surface.hxx>
 #include <TopExp_Explorer.hxx>
 #include <TopoDS.hxx>
+#include <BRepAlgoAPI_Common.hxx>
 #include <BRepGProp.hxx>
 #include <GProp_GProps.hxx>
 #include <BRepPrimAPI_MakeBox.hxx>
@@ -772,16 +774,10 @@ TEST_CASE("entity constraints: tangent/midpoint/symmetric/angle", "[CadDocument]
 
 TEST_CASE("imported text glyphs all extrude without failing (charset sweep)", "[CadDocument]")
 {
-    std::string font = resources_dir().empty()
-        ? std::string("resources/fonts/HarmonyOS_Sans_SC_Regular.ttf")
-        : resources_dir() + "/fonts/HarmonyOS_Sans_SC_Regular.ttf";
-    {
-        std::ifstream probe(font);
-        if (!probe.good()) {
-            SUCCEED("bundled font not reachable in this environment; covered live on :10");
-            return;
-        }
-    }
+    // The bundled font, from the source tree: PROFILES_DIR is <repo>/resources/profiles.
+    const std::string font =
+        (boost::filesystem::path(PROFILES_DIR).parent_path() / "fonts" / "HarmonyOS_Sans_SC_Regular.ttf").string();
+    REQUIRE(std::ifstream(font).good());
 
     const std::string charset =
         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
@@ -2853,9 +2849,10 @@ TEST_CASE("datum coordinate system: non-perpendicular inputs produce orthonormal
     using Catch::Matchers::WithinAbs;
 
     CadDocument doc;
-    // Build a body so we have a face to reference for FaceAndDirection.
-    int sk = doc.add_sketch(SketchShape::Rectangle, SketchPlane::XY(), 20, 20, 10, "Box");
-    doc.add_extrude(sk, 10.0, false, BooleanMode::New, "BoxExt");
+    // A cylinder's end cap is bounded by one closed circular edge, which offers no in-plane
+    // direction, so the frame has to fall back on coordsys_x_hint.
+    int sk = doc.add_sketch(SketchShape::Circle, SketchPlane::XY(), 0, 0, 5.0, "Circle");
+    doc.add_extrude(sk, 10.0, false, BooleanMode::New, "Cyl");
     REQUIRE(doc.recompute());
     REQUIRE(doc.bodies.size() == 1);
     int n_faces = GeometryEngine::face_count(doc.bodies[0].shape);
@@ -2865,34 +2862,33 @@ TEST_CASE("datum coordinate system: non-perpendicular inputs produce orthonormal
         if (fn.z() > 0.9) { top_face = i; break; }
     }
     REQUIRE(top_face >= 0);
+    const Vec3d Z = GeometryEngine::face_normal_world(GeometryEngine::face_by_index(doc.bodies[0].shape, top_face));
 
     int cs = doc.add_coordsys(CoordSysType::PointWorld, Vec3d(0, 0, 0), "CS1");
     REQUIRE(cs >= 0);
     doc.features[cs].coordsys_type   = CoordSysType::FaceAndDirection;
     doc.features[cs].coordsys_body   = 0;
     doc.features[cs].coordsys_face   = top_face;
-    // Deliberately non-perpendicular X hint (NOT orthogonal to face normal ~+Z).
+    // Deliberately non-perpendicular X hint (NOT orthogonal to the face normal +Z).
     doc.features[cs].coordsys_x_hint = Vec3d(3.0, -1.0, 0.5);
 
     auto css = doc.resolve_datum_coordsys();
     REQUIRE(css.size() == 1);
     REQUIRE(css[0].error.empty());
 
-    Vec3d X = css[0].x, Y = css[0].y;
-    // Orthonormality: each axis has unit length
+    const Vec3d X = css[0].x, Y = css[0].y;
+    // X is the hint projected into the face plane.
+    const Vec3d expected_x = Vec3d(3.0, -1.0, 0.0).normalized();
+    CHECK_THAT(X.x(), WithinAbs(expected_x.x(), 1e-9));
+    CHECK_THAT(X.y(), WithinAbs(expected_x.y(), 1e-9));
+    CHECK_THAT(X.z(), WithinAbs(expected_x.z(), 1e-9));
+    // Orthonormal, with Z the face normal and the frame right-handed.
     CHECK_THAT(X.norm(), WithinAbs(1.0, 1e-9));
     CHECK_THAT(Y.norm(), WithinAbs(1.0, 1e-9));
-    // Pairwise dot products are ~0
-    CHECK_THAT(std::abs(X.dot(Y)), WithinAbs(0.0, 1e-9));
-    // Z = X x Y (derived), also unit and perpendicular
-    Vec3d Z = X.cross(Y);
-    CHECK_THAT(Z.norm(), WithinAbs(1.0, 1e-9));
-    CHECK_THAT(std::abs(X.dot(Z)), WithinAbs(0.0, 1e-9));
-    CHECK_THAT(std::abs(Y.dot(Z)), WithinAbs(0.0, 1e-9));
-    // Right-handedness: X x Y == Z
-    CHECK_THAT(Z.x(), WithinAbs((X.cross(Y)).x(), 1e-9));
-    CHECK_THAT(Z.y(), WithinAbs((X.cross(Y)).y(), 1e-9));
-    CHECK_THAT(Z.z(), WithinAbs((X.cross(Y)).z(), 1e-9));
+    CHECK_THAT(X.dot(Y), WithinAbs(0.0, 1e-9));
+    CHECK_THAT(X.dot(Z), WithinAbs(0.0, 1e-9));
+    CHECK_THAT(Y.dot(Z), WithinAbs(0.0, 1e-9));
+    CHECK_THAT(X.cross(Y).dot(Z), WithinAbs(1.0, 1e-9));
 }
 
 TEST_CASE("datum coordinate system: a face-only frame rotates with its body", "[CadDocument]")
@@ -3917,17 +3913,23 @@ TEST_CASE("Use/Convert Entities: construction references never become solid", "[
     }
     REQUIRE(top_face >= 0);
 
-    const size_t body_count_before = doc.bodies.size();
-    const double volume_before     = doc.body_mass_properties(0).volume;
-
     int target   = doc.add_sketch_entities({}, SketchPlane::XY(), "Use");
     int appended = doc.project_edges_into_sketch(target, 0, {}, top_face);
     REQUIRE(appended == 4);
+    doc.add_extrude(target, 5.0, false, BooleanMode::New, "UseExt");
 
-    REQUIRE(doc.recompute());
-    REQUIRE(doc.error.empty());
-    REQUIRE(doc.bodies.size() == body_count_before);
-    REQUIRE_THAT(doc.body_mass_properties(0).volume, WithinRel(volume_before, 1e-9));
+    SECTION("construction edges form no profile, so the extrude fails") {
+        REQUIRE_FALSE(doc.recompute());
+        REQUIRE_FALSE(doc.error.empty());
+    }
+    SECTION("the same edges as solid geometry extrude a 20x20x5 body") {
+        for (auto& e : doc.features[target].entities)
+            e.construction = false;
+        REQUIRE(doc.recompute());
+        REQUIRE(doc.error.empty());
+        REQUIRE(doc.bodies.size() == 2);
+        REQUIRE_THAT(doc.body_mass_properties(1).volume, WithinRel(20.0 * 20.0 * 5.0, 1e-6));
+    }
 }
 
 TEST_CASE("Use/Convert Entities: bad references return -1 and change nothing", "[CadDocument][project]")
@@ -4252,7 +4254,7 @@ TEST_CASE("a previous-format recipe is refused, not silently misread", "[CadDocu
     REQUIRE(doc.features.empty());   // nothing half-read was left behind
 }
 
-TEST_CASE("golden recipe v1 still deserialises", "[CadDocument]")
+TEST_CASE("a v4 recipe keeps every field value", "[CadDocument]")
 {
     using Catch::Matchers::WithinRel;
     using Catch::Matchers::WithinAbs;
@@ -4282,20 +4284,16 @@ TEST_CASE("golden recipe v1 still deserialises", "[CadDocument]")
     }
 
     CadDocument expected = make_golden_doc_v1();
-    // Scoped tightly: this advice is ONLY valid for a count mismatch. It must not be in
-    // scope for the field-value assertions below, where "regenerate the fixture" is the
-    // one thing you must never do -- regenerating after a reorder bakes the corrupted
-    // layout in as the new golden and permanently disarms this test.
     {
-        INFO("Feature count changed - did you add/remove features in make_golden_doc_v1()?");
-        INFO("If so: run libslic3r_tests \"[.regen]\" and re-run this test.");
+        INFO("Feature count changed - make_golden_doc_v1() must keep building exactly the tree "
+             "frozen in cad_recipe_v4.bin, so do not add or remove features there.");
         REQUIRE(features.size() == expected.features.size());
     }
 
     // A failure BELOW this point means the on-disk serialization format changed: some field
     // in CadFeature::save/load was reordered, retyped, or removed. Fields may only ever be
     // APPENDED at the end of both lists. Do NOT regenerate the fixture to make this pass --
-    // fix the field order instead. See scripts/CAD/run-kernel-tests.sh and the [.regen] case.
+    // fix the field order instead.
 
     // Field-by-field assertions against expected values.
     // Every field set to a distinctive non-default literal must be checked here.
@@ -4550,34 +4548,48 @@ TEST_CASE("golden recipe v1 still deserialises", "[CadDocument]")
         }
     }
 
-    // --- Layer 2: geometry check (optional — only if the document recomputes) ---
-    // Build expected document and try to recompute it.
-    // ponytail: the field-value layer above is the real tripwire;
-    // this layer is a bonus sanity check on the full recompute path.
+    // --- Layer 2: the production v4 load rebuilds the same geometry as the in-memory tree ---
+    // The golden tree is serialization coverage and does not recompute as a whole: these
+    // features fail on the geometry they get, so they are left off in both trees.
+    const std::set<std::string> unbuildable{"Fillet_Lat35", "Chamfer_Top2", "Draft_F3", "Shell_T1375",
+                                            "GoldenProject"};
     CadDocument exp_doc = make_golden_doc_v1();
-    bool exp_ok = exp_doc.recompute();
-    if (!exp_ok) {
-        INFO("Expected document from make_golden_doc_v1() could not recompute "
-             "(complex feature tree). Field-value checks above are sufficient.");
+    // Fields appended after v4 are not in the file, so a v4 project reads them as defaults
+    // (a v4 thread, for one, is not major-nominal). The reference has to match that.
+    const CadFeature def;
+    for (CadFeature& f : exp_doc.features) {
+        f.thread_major_nominal = def.thread_major_nominal;
+        f.pattern_inclusive    = def.pattern_inclusive;
+        f.dressup_edges        = def.dressup_edges;
+        f.text_string          = def.text_string;
+        f.text_font            = def.text_font;
+        f.text_height          = def.text_height;
+        f.revolve_axis_entity  = def.revolve_axis_entity;
     }
-
     CadDocument doc;
-    bool ser_ok = doc.deserialize_recipe(blob);
-
-    if (exp_ok && ser_ok) {
-        REQUIRE(doc.error.empty());
-        REQUIRE(doc.bodies.size() == exp_doc.bodies.size());
-        for (size_t i = 0; i < doc.bodies.size(); ++i) {
-            double v = double(SketchEngine::tessellate(doc.bodies[i].shape).volume());
-            double ev = double(SketchEngine::tessellate(exp_doc.bodies[i].shape).volume());
-            REQUIRE_THAT(v, WithinRel(ev, 1e-6));
+    doc.deserialize_recipe(blob);
+    REQUIRE(doc.features.size() == exp_doc.features.size());
+    for (size_t i = 0; i < exp_doc.features.size(); ++i)
+        exp_doc.features[i].enabled = doc.features[i].enabled = unbuildable.count(exp_doc.features[i].name) == 0;
+    const bool exp_built = exp_doc.recompute();
+    INFO("reference error: " << exp_doc.error);
+    REQUIRE(exp_built);
+    const bool built = doc.recompute();
+    INFO("loaded error: " << doc.error);
+    REQUIRE(built);
+    REQUIRE_FALSE(exp_doc.bodies.empty());
+    REQUIRE(doc.bodies.size() == exp_doc.bodies.size());
+    for (size_t b = 0; b < doc.bodies.size(); ++b) {
+        INFO("body " << b);
+        TriangleMesh mesh     = SketchEngine::tessellate(doc.bodies[b].shape);
+        TriangleMesh exp_mesh = SketchEngine::tessellate(exp_doc.bodies[b].shape);
+        CHECK_THAT(double(mesh.volume()), WithinRel(double(exp_mesh.volume()), 1e-6));
+        // Volume alone is blind to fields that only place a body, such as a transform.
+        const BoundingBoxf3 bb = mesh.bounding_box(), exp_bb = exp_mesh.bounding_box();
+        for (int k = 0; k < 3; ++k) {
+            CHECK_THAT(bb.min[k], WithinAbs(exp_bb.min[k], 1e-6));
+            CHECK_THAT(bb.max[k], WithinAbs(exp_bb.max[k], 1e-6));
         }
-    } else {
-        INFO("The golden recipe fixture was loaded and field-value checks passed.");
-        INFO("Recompute on the deserialized or expected document failed — this is");
-        INFO("expected for the extended golden fixture (many feature types coexist");
-        INFO("purely for serialization coverage). The field-value tripwire above is");
-        INFO("the primary format check.");
     }
 }
 
@@ -5781,8 +5793,9 @@ TEST_CASE("fastened mate with angle", "[CadDocument][mate]")
     REQUIRE(doc.recompute());
     REQUIRE(doc.error.empty());
 
-    int sk2 = doc.add_sketch(SketchShape::Circle, SketchPlane::XY(), 0, 0, 3, "Cyl");
-    doc.add_extrude(sk2, 10.0, false, BooleanMode::New, "CylExt");
+    // A 20x10 plate, so a quarter turn about the connector's Z swaps its X and Y extents.
+    int sk2 = doc.add_sketch(SketchShape::Rectangle, SketchPlane::XY(), 20, 10, 0, "Plate");
+    doc.add_extrude(sk2, 10.0, false, BooleanMode::New, "PlateExt");
     REQUIRE(doc.recompute());
     REQUIRE(doc.error.empty());
 
@@ -5801,6 +5814,13 @@ TEST_CASE("fastened mate with angle", "[CadDocument][mate]")
     gp_Pnt com = props.CentreOfMass();
     REQUIRE_THAT(double(com.X()), WithinAbs(5.0, 1e-4));
     REQUIRE_THAT(double(com.Y()), WithinAbs(5.0, 1e-4));
+
+    Bnd_Box bb;
+    BRepBndLib::Add(doc.bodies[1].shape, bb);
+    double x0, y0, z0, x1, y1, z1;
+    bb.Get(x0, y0, z0, x1, y1, z1);
+    REQUIRE_THAT(x1 - x0, WithinAbs(10.0, 1e-3));
+    REQUIRE_THAT(y1 - y0, WithinAbs(20.0, 1e-3));
 }
 
 TEST_CASE("fastened mate with flip", "[CadDocument][mate]")
@@ -5823,7 +5843,9 @@ TEST_CASE("fastened mate with flip", "[CadDocument][mate]")
     REQUIRE(doc.recompute());
     REQUIRE(doc.error.empty());
 
-    int cs_moving = doc.add_coordsys(CoordSysType::PointWorld, Vec3d(0, 0, 5), "CS_Moving");
+    // The connector sits on the cylinder's base, so the flip decides which side of the
+    // fixed connector (z = 5) the 10 mm cylinder hangs: above it unflipped, below it flipped.
+    int cs_moving = doc.add_coordsys(CoordSysType::PointWorld, Vec3d(0, 0, 0), "CS_Moving");
     doc.features[cs_moving].coordsys_body = 1;
     REQUIRE(doc.recompute());
     REQUIRE(doc.error.empty());
@@ -5837,8 +5859,7 @@ TEST_CASE("fastened mate with flip", "[CadDocument][mate]")
     gp_Pnt com = props.CentreOfMass();
     REQUIRE_THAT(double(com.X()), WithinAbs(5.0, 1e-4));
     REQUIRE_THAT(double(com.Y()), WithinAbs(5.0, 1e-4));
-    // Flip opposes Z axes: for a symmetric cylinder this is invisible in centroid,
-    // but the mate executed cleanly and the body moved to the target connector.
+    REQUIRE_THAT(double(com.Z()), WithinAbs(5.0 - 10.0 / 2, 1e-4));
 }
 
 TEST_CASE("planar mate: normal distance becomes mate_offset", "[CadDocument][mate]")
@@ -6525,23 +6546,19 @@ TEST_CASE("fastened mate with flip on asymmetric body", "[CadDocument][mate]")
     REQUIRE(doc.recompute());
     REQUIRE(doc.error.empty());
 
-    // Fastened, NO flip
-    doc.add_mate(0, cs_fixed, cs_moving, 0.0, 0.0, false, "MateNoFlip");
-    REQUIRE(doc.recompute());
-    REQUIRE(doc.error.empty());
-    GProp_GProps nf_props;
-    BRepGProp::VolumeProperties(doc.bodies[1].shape, nf_props);
-    double nf_z = nf_props.CentreOfMass().Z();
-
-    doc.undo();
-
-    // Fastened, WITH flip
-    doc.add_mate(0, cs_fixed, cs_moving, 0.0, 0.0, true, "MateFlip");
-    REQUIRE(doc.recompute());
-    REQUIRE(doc.error.empty());
-    GProp_GProps f_props;
-    BRepGProp::VolumeProperties(doc.bodies[1].shape, f_props);
-    double f_z = f_props.CentreOfMass().Z();
+    // The same assembly mated once without and once with flip, each in its own copy.
+    auto mated_com_z = [&](bool flip) {
+        CadDocument d = doc;
+        d.add_mate(0, cs_fixed, cs_moving, 0.0, 0.0, flip, "Mate");
+        REQUIRE(d.recompute());
+        REQUIRE(d.error.empty());
+        REQUIRE(d.mate_conflicts.empty());
+        GProp_GProps props;
+        BRepGProp::VolumeProperties(d.bodies[1].shape, props);
+        return props.CentreOfMass().Z();
+    };
+    const double nf_z = mated_com_z(false);
+    const double f_z  = mated_com_z(true);
 
     // Flip changes the centroid Z for an asymmetric body
     REQUIRE_THAT(f_z, !WithinAbs(nf_z, 1e-4));
@@ -7324,13 +7341,22 @@ TEST_CASE("interference: sheet bodies are skipped", "[CadDocument][interference]
     CadDocument doc;
     int sk_a = doc.add_sketch(SketchShape::Rectangle, SketchPlane::XY(), 20, 20, 0, "BoxA");
     doc.add_extrude(sk_a, 10.0, false, BooleanMode::New, "EA");
-    // A sheet passing straight through the solid: it has no volume, so no interference.
-    int sk_s = doc.add_sketch(SketchShape::Rectangle, SketchPlane::XY(), 40, 40, 0, "Sheet");
+    // Four 10x5 walls standing inside the 20x20x10 solid: a sheet has no volume, so no interference.
+    int sk_s = doc.add_sketch(SketchShape::Rectangle, SketchPlane::XY(), 10, 10, 0, "Sheet");
     doc.add_surface_extrude(sk_s, 5.0, "SE");
     REQUIRE(doc.recompute());
     REQUIRE(doc.bodies.size() == 2);
     REQUIRE(CadDocument::is_sheet_shape(doc.bodies[1].shape));
 
+    // The raw overlap of the walls with the solid does measure a volume, so only the sheet
+    // skip keeps it out of the report.
+    BRepAlgoAPI_Common common(doc.bodies[0].shape, doc.bodies[1].shape);
+    common.Build();
+    REQUIRE(common.IsDone());
+    GProp_GProps props;
+    BRepGProp::VolumeProperties(common.Shape(), props);
+    REQUIRE(std::abs(props.Mass()) > 1e-6);
+
     REQUIRE(doc.check_interference().empty());
 }
 
@@ -7540,9 +7566,8 @@ TEST_CASE("A cut that removes no material is an error, not a silent success", "[
         CHECK(doc.error.find("removed no material") != std::string::npos);
 
         // And the body is left as it was, not half-applied.
-        CadDocument again = box();
-        REQUIRE(again.recompute());
-        CHECK_THAT(again.body_mass_properties(0).volume,
+        REQUIRE(doc.bodies.size() == 1);
+        CHECK_THAT(doc.body_mass_properties(0).volume,
                    Catch::Matchers::WithinAbs(solid, 1e-6));
     }
 

tests/libslic3r/test_config.cpp

@@ -75,11 +75,10 @@ SCENARIO("Config accessor functions perform as expected.", "[Config]") {
             }
         }
         WHEN("A boolean option is set to a string value representing something other than 0 or 1") {
-            THEN("A BadOptionTypeException exception is thrown.") {
+            config.set("gcode_comments", true);
+            THEN("A BadOptionTypeException exception is thrown and the value is unchanged.") {
                 REQUIRE_THROWS_AS(config.set("gcode_comments", "Z"), BadOptionTypeException);
-            }
-            AND_THEN("Value is unchanged.") {
-                REQUIRE(config.opt<ConfigOptionBool>("gcode_comments")->getBool() == false);
+                REQUIRE(config.opt<ConfigOptionBool>("gcode_comments")->getBool() == true);
             }
         }
         WHEN("A boolean option is set to an int value") {
@@ -117,12 +116,10 @@ SCENARIO("Config accessor functions perform as expected.", "[Config]") {
             }
         }
         WHEN("A numeric option is set to a non-numeric value.") {
-	    auto prev_value = config.opt<ConfigOptionFloat>("max_bridge_length")->getFloat();
-            THEN("A BadOptionTypeException exception is thrown.") {
+            config.set("max_bridge_length", 7.5);
+            THEN("A BadOptionValueException exception is thrown and the value does not change.") {
                 REQUIRE_THROWS_AS(config.set_deserialize_strict("max_bridge_length", "zzzz"), BadOptionValueException);
-            }
-            THEN("The value does not change.") {
-                REQUIRE(config.opt<ConfigOptionFloat>("max_bridge_length")->getFloat() == prev_value);
+                REQUIRE_THAT(config.opt<ConfigOptionFloat>("max_bridge_length")->getFloat(), Catch::Matchers::WithinAbs(7.5, 1e-9));
             }
         }
         WHEN("A string option is set through the string interface") {
@@ -198,7 +195,7 @@ SCENARIO("Config accessor functions perform as expected.", "[Config]") {
 	    }
         }
         WHEN("An invalid option is requested during set.") {
-            THEN("A BadOptionTypeException exception is thrown.") {
+            THEN("A UnknownOptionException exception is thrown.") {
                 REQUIRE_THROWS_AS(config.set("deadbeef_invalid_option", 1), UnknownOptionException);
                 REQUIRE_THROWS_AS(config.set("deadbeef_invalid_option", 1.0), UnknownOptionException);
                 REQUIRE_THROWS_AS(config.set("deadbeef_invalid_option", "1"), UnknownOptionException);

tests/libslic3r/test_filament_mixer.cpp

@@ -65,41 +65,25 @@ TEST_CASE("expand_mixed_filaments replaces mixed slots with their components", "
     }
 }
 
-TEST_CASE("belt purge tower island count ignores virtual mixed slots", "[FilamentMixer][belt]")
+TEST_CASE("A mixed slot whose components are already used adds no filaments", "[FilamentMixer][belt]")
 {
-    // Regression for the "extra purge tower" on a belt printer with a mixed
-    // filament (MCTEST5). The belt purge prism is sized as
-    //   n_islands = used_filaments.size() - 1
-    // and GUI::ensure_belt_purge_tower() collected those filaments straight off
-    // the model objects' extruder assignments. A mixed slot is VIRTUAL -- no
-    // nozzle carries it, and ToolOrdering::resolve_mixed_filaments() replaces it
-    // with its components before any G-code is emitted -- so counting it as a
-    // filament of its own provisions one island that can never be reached.
-    //
-    // MCTEST5: five cubes on extruders 1..5, where filament 5 is a 50/50 blend of
-    // filaments 2 and 4. The G-code uses only T0..T3 and reports
-    // "filament used [g] = 53.35, 141.11, 40.84, 107.23, 0.00" -- filament 5
-    // consumes nothing, exactly as a virtual slot should.
+    // The belt purge tower sizes its islands from the expanded set. A mixed slot is virtual: no
+    // nozzle carries it and ToolOrdering::resolve_mixed_filaments() replaces it with its
+    // components, so it must not count as a filament of its own.
     const std::vector<unsigned char> is_mixed  = {0, 0, 0, 0, 1};
     const std::vector<std::string>   comp_strs = {"", "", "", "", "2,4"};
 
-    // The set the sizer used to see: slots 0..4 (filaments 1..5).
     const std::vector<unsigned int> assigned = {0, 1, 2, 3, 4};
     const auto physical = expand_mixed_filaments(assigned, is_mixed, comp_strs);
 
     // Slot 4 dissolves into 1 and 3, which are already present.
     REQUIRE(physical == std::vector<unsigned int>({0, 1, 2, 3}));
 
-    // Four physical filaments => three transitions => three islands, not four.
-    REQUIRE(int(physical.size()) - 1 == 3);
-    REQUIRE(int(assigned.size()) - 1 == 4);   // what it produced before the fix
-
     SECTION("A mixed slot whose components are otherwise unused still counts them") {
-        // Only the mixed slot is assigned: it must still yield its two components,
-        // i.e. one island, rather than collapsing to zero.
+        // Only the mixed slot is assigned: it must still yield its two components rather than
+        // collapsing to nothing.
         const auto only_mixed = expand_mixed_filaments({4}, is_mixed, comp_strs);
         REQUIRE(only_mixed == std::vector<unsigned int>({1, 3}));
-        REQUIRE(int(only_mixed.size()) - 1 == 1);
     }
 
     SECTION("No mixed filaments anywhere leaves the set untouched") {

tests/libslic3r/test_preset_bundle_loading.cpp

@@ -1334,12 +1334,17 @@ TEST_CASE("Renamed printer/process names are normalized into compatible lists on
     CHECK(compatible_list(bundle.filaments, "My Filament", "compatible_printers") ==
           (std::vector<std::string>{ "New Printer", "Unknown Printer" }));
 
-    // Normalizing rewrites config in place without flagging the preset dirty.
-    CHECK_FALSE(bundle.prints.find_preset("My Process", false, true)->is_dirty);
+    // Normalization runs before selection, so selecting copies the rewritten list into the edited preset.
+    bundle.prints.select_preset_by_name("My Process", true);
+    REQUIRE(bundle.prints.get_selected_preset_name() == "My Process");
+    CHECK(bundle.prints.get_edited_preset().config.option<ConfigOptionStrings>("compatible_printers")->values ==
+          std::vector<std::string>{ "New Printer" });
 
-    // A system preset that already references the current name is left untouched (idempotent no-op).
+    // Normalizing again is a no-op: the stored preset keeps the current name and still matches the
+    // edited copy, so the selection is not reported modified.
     bundle.normalize_compatible_presets();
     CHECK(compatible_list(bundle.prints, "My Process", "compatible_printers") == std::vector<std::string>{ "New Printer" });
+    CHECK_FALSE(bundle.prints.current_is_dirty());
 }
 
 TEST_CASE("Renamed names are normalized into a SYSTEM preset's compatible lists", "[Preset][Rename]")
@@ -1369,11 +1374,17 @@ TEST_CASE("Renamed names are normalized into a SYSTEM preset's compatible lists"
     CHECK(compatible_list(bundle.filaments, "System Filament", "compatible_prints") ==
           std::vector<std::string>{ "New Process" });
 
-    // The rewrite does not flag the system preset dirty, and is idempotent.
-    CHECK_FALSE(bundle.filaments.find_preset("System Filament", false, true)->is_dirty);
+    // Normalization runs before selection, so selecting copies the rewritten lists into the edited preset.
+    bundle.filaments.select_preset_by_name("System Filament", true);
+    REQUIRE(bundle.filaments.get_selected_preset_name() == "System Filament");
+    CHECK(bundle.filaments.get_edited_preset().config.option<ConfigOptionStrings>("compatible_printers")->values ==
+          std::vector<std::string>{ "New Printer" });
+
+    // Normalizing again is a no-op, so the selection is not reported modified.
     bundle.normalize_compatible_presets();
     CHECK(compatible_list(bundle.filaments, "System Filament", "compatible_printers") ==
           std::vector<std::string>{ "New Printer" });
+    CHECK_FALSE(bundle.filaments.current_is_dirty());
 }
 
 TEST_CASE("compatible_prints on SLA materials resolves against sla_prints, not prints", "[Preset][Rename]")
@@ -5566,16 +5577,6 @@ TEST_CASE("Sizing down to the nozzle count plus mixes is what eats the mixed tai
         CHECK(bundle.num_mixed_filaments() == 0);
         CHECK(bundle.num_physical_filaments() == target);
     }
-
-    SECTION("applied as a floor, the mix is left alone") {
-        if (target > bundle.filament_presets.size())
-            bundle.set_num_filaments(target);
-
-        CHECK(bundle.filament_presets.size() == 6);
-        CHECK(bundle.num_mixed_filaments() == 1);
-        CHECK(bundle.is_mixed_filament(5));
-        CHECK(bundle.project_config.option<ConfigOptionStrings>("filament_mixed_components")->values[5] == "1,2");
-    }
 }
 
 // After a published-3MF import relocated mixed-filament definitions, the freshly loaded

tests/libslic3r/test_sketchimport.cpp

@@ -5,9 +5,9 @@
 #include <catch2/matchers/catch_matchers.hpp>
 #include <catch2/matchers/catch_matchers_floating_point.hpp>
 #include "libslic3r/CAD/SketchImport.hpp"
-#include "libslic3r/Utils.hpp"   // resources_dir
 #include "test_utils.hpp"        // ScopedTemporaryFile
 
+#include <boost/filesystem/path.hpp>
 #include <cstdlib>
 #include <fstream>
 #include "libslic3r/Point.hpp"
@@ -78,18 +78,10 @@ TEST_CASE("transform_regions moves and scales independently", "[SketchImport]")
 
 TEST_CASE("text_to_regions vectorizes glyphs with counters", "[SketchImport]")
 {
-    // Locate the bundled font; resources_dir() may be unset under ctest, so
-    // fall back to a cwd-relative path (tests run from the repo root).
-    std::string font = resources_dir().empty()
-                           ? std::string("resources/fonts/HarmonyOS_Sans_SC_Regular.ttf")
-                           : resources_dir() + "/fonts/HarmonyOS_Sans_SC_Regular.ttf";
-    {
-        std::ifstream probe(font);
-        if (!probe.good()) {
-            SUCCEED("bundled font not reachable in this environment; covered live on :10");
-            return;
-        }
-    }
+    // The bundled font, from the source tree: PROFILES_DIR is <repo>/resources/profiles.
+    const std::string font =
+        (boost::filesystem::path(PROFILES_DIR).parent_path() / "fonts" / "HarmonyOS_Sans_SC_Regular.ttf").string();
+    REQUIRE(std::ifstream(font).good());
 
     // Bad input is rejected without throwing.
     REQUIRE(text_to_regions("", 10.0, font).empty());

tests/libslic3r/test_sketchinference.cpp

@@ -33,8 +33,9 @@ TEST_CASE("inference: cursor near a line endpoint snaps Coincident-able to it",
 TEST_CASE("inference: endpoint beats midpoint when both are in range", "[inference]")
 {
     std::vector<SketchEntity> ents = { line({0, 0}, {2, 0}) };
-    // Query equidistant-ish but closer to the endpoint: endpoint tier wins regardless.
-    auto s = infer_point_snap(ents, {1.9, 0.0}, 5.0);
+    // Query 0.2 from the midpoint (1,0) and 0.8 from the endpoint (2,0): the endpoint tier
+    // wins even though the midpoint is nearer.
+    auto s = infer_point_snap(ents, {1.2, 0.0}, 5.0, /*include_origin=*/false);
     CHECK(s.kind == K::Endpoint);
     CHECK(s.role == SketchPointRole::P1);
 }

tests/libslic3r/test_sketchprofile.cpp

@@ -113,14 +113,11 @@ TEST_CASE("profile: offsetting a closed rectangle keeps it closed", "[SketchProf
     REQUIRE(closed_wires(out) == 1);
 }
 
-TEST_CASE("profile: offset outward grows the enclosed area by the right amount", "[SketchProfile]")
+TEST_CASE("profile: offsetting a closed rectangle outward keeps it one closed loop", "[SketchProfile]")
 {
-    // A rectangle offset outward by d is (w+2d) x (h+2d) with the corners rounded at r=d,
-    // so its area is w*h + 2d(w+h) + pi*d^2 whichever way the corners are healed... except
-    // for a sharp-corner offset, which is exactly (w+2d)*(h+2d). Either healing is defensible;
-    // a set of four disconnected segments is not, and that is what this measures.
-    const double w = 40, h = 20, d = 5;
-    const auto out = SketchEngine::offset_entities(rect(w, h), d);
+    // Outward is -d for a CCW loop. The miter join reconnects the corners, so the result is one
+    // closed wire, not four disconnected segments. Its area is checked by the sign test below.
+    const auto out = SketchEngine::offset_entities(rect(40, 20), -5.0);
     const auto ws  = SketchEngine::entities_to_wires(out, xy_plane());
     REQUIRE(ws.size() == 1);
     REQUIRE(ws[0].Closed());

tests/libslic3r/test_toolordering_nozzle_group.cpp

@@ -60,9 +60,8 @@ std::vector<NozzleInfo> single_nozzle_per_extruder(int extruder_count)
 }
 } // namespace
 
-TEST_CASE("Multi-nozzle gate predicate mirrors BambuStudio", "[ToolOrdering][H2C]")
+TEST_CASE("Multi-nozzle options exist and default to one nozzle per extruder", "[ToolOrdering][H2C]")
 {
-    // The multi-nozzle gate: std::any_of(extruder_max_nozzle_count > 1).
     DynamicPrintConfig config = DynamicPrintConfig::full_print_config();
 
     auto *opt = config.option<ConfigOptionIntsNullable>("extruder_max_nozzle_count");
@@ -72,15 +71,11 @@ TEST_CASE("Multi-nozzle gate predicate mirrors BambuStudio", "[ToolOrdering][H2C
     // 3mf projects round-trip the per-extruder nozzle inventory (GUI producers wire it later).
     REQUIRE(config.option<ConfigOptionStrings>("extruder_nozzle_stats") != nullptr);
 
-    auto has_multiple_nozzle = [](const std::vector<int> &values) {
-        return std::any_of(values.begin(), values.end(), [](int v) { return v > 1; });
-    };
-
-    // Default for every existing printer: 1 nozzle per extruder => gate is closed.
-    REQUIRE_FALSE(has_multiple_nozzle(opt->values));
-
-    // Synthetic H2C-like machine: extruder 1 is a 6-nozzle cluster => gate opens.
-    REQUIRE(has_multiple_nozzle(std::vector<int>{1, 6}));
+    // Default for every existing printer: 1 nozzle per extruder, so the multi-nozzle gate
+    // (any extruder_max_nozzle_count > 1) stays closed.
+    REQUIRE_FALSE(opt->values.empty());
+    for (int count : opt->values)
+        CHECK(count == 1);
 }
 
 TEST_CASE("Single-nozzle grouping: every filament maps to its extruder nozzle", "[ToolOrdering][H2C]")

tests/libslic3r/test_voronoi.cpp

@@ -32,6 +32,7 @@
 using namespace Slic3r;
 
 using VD = Geometry::VoronoiDiagram;
+static bool has_missing_voronoi_vertices(const Polygons &polygons, const VD &vd);
 using BoostVD = boost::polygon::voronoi_diagram<double>;
 
 // https://svn.boost.org/trac10/ticket/12067
@@ -198,8 +199,12 @@ TEST_CASE("Voronoi missing edges - Alessandro gapfill 12707", "[Voronoi]")
     REQUIRE(intersecting_edges({ poly }).empty());
 
     Lines lines = to_lines(poly);
-    BoostVD vd;
-    construct_voronoi(lines.begin(), lines.end(), &vd);
+    VD vd;
+    vd.construct_voronoi(lines.begin(), lines.end());
+    // Orca's detector finds nothing wrong with this input, so no repair is needed.
+    CHECK(VD::detect_known_issues(vd, lines.begin(), lines.end()) == VD::IssueType::NO_ISSUE_DETECTED);
+    CHECK(vd.get_state() == VD::State::REPAIR_NOT_NEEDED);
+    CHECK_FALSE(has_missing_voronoi_vertices({ poly }, vd));
 
 #ifdef VORONOI_DEBUG_OUT
     dump_voronoi_to_svg(debug_out_path("voronoi-lines.svg").c_str(),
@@ -305,9 +310,16 @@ TEST_CASE("Voronoi weirdness", "[Voronoi]")
     }
 #endif
 
-    BoostVD vd;
+    VD vd;
     Lines lines = to_lines(poly);
-    construct_voronoi(lines.begin(), lines.end(), &vd);
+    vd.construct_voronoi(lines.begin(), lines.end());
+    // Unrepaired, the diagram is missing a Voronoi vertex. construct_voronoi detects it and repairs it
+    // by rotating the input.
+    VD raw_vd;
+    raw_vd.construct_voronoi(lines.begin(), lines.end(), false);
+    CHECK(VD::detect_known_issues(raw_vd, lines.begin(), lines.end()) == VD::IssueType::MISSING_VORONOI_VERTEX);
+    CHECK(vd.get_state() == VD::State::REPAIR_SUCCESSFUL);
+    CHECK(vd.get_issue_type() == VD::IssueType::NO_ISSUE_DETECTED);
 
 #ifdef VORONOI_DEBUG_OUT
     dump_voronoi_to_svg(debug_out_path("voronoi-weirdness.svg").c_str(),
@@ -347,9 +359,8 @@ TEST_CASE("Voronoi division by zero 12903", "[Voronoi]")
 
 // https://svn.boost.org/trac10/ticket/12139
 // Funny sample from a dental industry?
-// Vojtech confirms this test fails and rightly so, because the input data contain self intersections.
-// This test is suppressed.
-TEST_CASE("Voronoi NaN coordinates 12139", "[Voronoi][.][!mayfail]")
+// The input data contain self intersections, so no valid Voronoi diagram can be built from it.
+TEST_CASE("Voronoi NaN coordinates 12139", "[Voronoi]")
 {
     Lines lines = {
         { {  260500,1564400 }, { 261040,1562960 } },
@@ -1327,18 +1338,13 @@ TEST_CASE("Voronoi NaN coordinates 12139", "[Voronoi][.][!mayfail]")
         }
 #endif
 
-    BoostVD vd;
-    construct_voronoi(lines.begin(), lines.end(), &vd);
-
-    for (const auto& edge : vd.edges())
-        if (edge.is_finite()) {
-            auto v0 = edge.vertex0();
-            auto v1 = edge.vertex1();
-            REQUIRE((v0->x() == 0 || std::isnormal(v0->x())));
-            REQUIRE((v0->y() == 0 || std::isnormal(v0->y())));
-            REQUIRE((v1->x() == 0 || std::isnormal(v1->x())));
-            REQUIRE((v1->y() == 0 || std::isnormal(v1->y())));
-        }
+    VD vd;
+    vd.construct_voronoi(lines.begin(), lines.end());
+    // The diagram built from this self-intersecting input has non-finite vertices, and rotating the
+    // input does not repair it. It must be reported as invalid, which is what MedialAxis::build
+    // checks before falling back to a morphological closing.
+    CHECK(vd.get_state() == VD::State::REPAIR_UNSUCCESSFUL);
+    CHECK_FALSE(vd.is_valid());
 
 #ifdef VORONOI_DEBUG_OUT
     dump_voronoi_to_svg(debug_out_path("voronoi-NaNs.svg").c_str(),
@@ -1935,7 +1941,7 @@ TEST_CASE("Voronoi skeleton", "[VoronoiSkeleton]")
 }
 
 // Simple detection with complexity N^2 if there is any point in the input polygons that doesn't have Voronoi vertex.
-[[maybe_unused]] static bool has_missing_voronoi_vertices(const Polygons &polygons, const VD &vd)
+static bool has_missing_voronoi_vertices(const Polygons &polygons, const VD &vd)
 {
     auto are_equal = [](const VD::vertex_type v, const Point &p) { return (Vec2d(v.x(), v.y()) - p.cast<double>()).norm() <= SCALED_EPSILON; };
 
@@ -1957,7 +1963,7 @@ TEST_CASE("Voronoi skeleton", "[VoronoiSkeleton]")
 // into two parts. Even we add more points to the edge, and then for these points, the Voronoin vertex is also missing. An
 // infinity-edge passes through the missing Voronoi vertex. Therefore, this missing Voronoi vertex and edge can be reconstructed
 // using the intersection between the infinity-edge with the input polygon.
-// Rotation of the polygon solves this problem.
+// VoronoiDiagram::construct_voronoi repairs it by rotating the input.
 TEST_CASE("Voronoi missing vertex 1", "[VoronoiMissingVertex1]")
 {
     Polygon poly = {
@@ -1981,7 +1987,14 @@ TEST_CASE("Voronoi missing vertex 1", "[VoronoiMissingVertex1]")
     dump_voronoi_to_svg(debug_out_path("voronoi-missing-vertex1-out.svg").c_str(), vd, Points(), lines);
 #endif
 
-//    REQUIRE(!has_missing_voronoi_vertices({poly}, vd));
+    // Unrepaired, the diagram shows the defect. construct_voronoi detects it and repairs it by
+    // rotating the input.
+    VD raw_vd;
+    raw_vd.construct_voronoi(lines.begin(), lines.end(), false);
+    CHECK(has_missing_voronoi_vertices({poly}, raw_vd));
+    CHECK(vd.get_state() == VD::State::REPAIR_SUCCESSFUL);
+    CHECK(vd.get_issue_type() == VD::IssueType::NO_ISSUE_DETECTED);
+    CHECK_FALSE(has_missing_voronoi_vertices({poly}, vd));
 }
 
 // This case is composed of two square polygons (contour and hole), and again one of the edges is divided into two parts by a
@@ -1989,7 +2002,7 @@ TEST_CASE("Voronoi missing vertex 1", "[VoronoiMissingVertex1]")
 // that for this case, through the missing Voronoi vertex is passing a finite edge between two internal Voronoin vertices.
 // Therefore, this missing Voronoi vertex and edge can be reconstructed using the intersection between the finite edge with the
 // input polygon.
-// Rotation of the polygons solves this problem.
+// VoronoiDiagram::construct_voronoi repairs it by rotating the input.
 TEST_CASE("Voronoi missing vertex 2", "[VoronoiMissingVertex2]")
 {
     Polygons poly = {
@@ -2021,13 +2034,20 @@ TEST_CASE("Voronoi missing vertex 2", "[VoronoiMissingVertex2]")
     dump_voronoi_to_svg(debug_out_path("voronoi-missing-vertex2-out.svg").c_str(), vd, Points(), lines);
 #endif
 
-//    REQUIRE(!has_missing_voronoi_vertices(poly, vd));
+    // Unrepaired, the diagram shows the defect. construct_voronoi detects it and repairs it by
+    // rotating the input.
+    VD raw_vd;
+    raw_vd.construct_voronoi(lines.begin(), lines.end(), false);
+    CHECK(has_missing_voronoi_vertices(poly, raw_vd));
+    CHECK(vd.get_state() == VD::State::REPAIR_SUCCESSFUL);
+    CHECK(vd.get_issue_type() == VD::IssueType::NO_ISSUE_DETECTED);
+    CHECK_FALSE(has_missing_voronoi_vertices(poly, vd));
 }
 
 // This case is composed of two polygons, and again one of the edges is divided into two parts by a point that lies on this edge,
 // and for this point is Voronoi vertex missing. A difference between the previous cases and this case through the missing
 // Voronoi vertex is passing finite edge between one inner Voronoi vertex and one outer Voronoi vertex.
-// Rotating the polygon also help solve this problem.
+// VoronoiDiagram::construct_voronoi repairs it by rotating the input.
 TEST_CASE("Voronoi missing vertex 3", "[VoronoiMissingVertex3]")
 {
     Polygons poly = {
@@ -2055,20 +2075,27 @@ TEST_CASE("Voronoi missing vertex 3", "[VoronoiMissingVertex3]")
     //    polygons_rotate(poly, PI/180);
     //    polygons_rotate(poly, PI/6);
 
-    BoostVD vd;
+    VD    vd;
     Lines lines = to_lines(poly);
-    construct_voronoi(lines.begin(), lines.end(), &vd);
+    vd.construct_voronoi(lines.begin(), lines.end());
 #ifdef VORONOI_DEBUG_OUT
     dump_voronoi_to_svg(debug_out_path("voronoi-missing-vertex3-out.svg").c_str(), vd, Points(), lines);
 #endif
 
-//    REQUIRE(!has_missing_voronoi_vertices(poly, vd));
+    // Unrepaired, the diagram shows the defect. construct_voronoi detects it and repairs it by
+    // rotating the input.
+    VD raw_vd;
+    raw_vd.construct_voronoi(lines.begin(), lines.end(), false);
+    CHECK(has_missing_voronoi_vertices(poly, raw_vd));
+    CHECK(vd.get_state() == VD::State::REPAIR_SUCCESSFUL);
+    CHECK(vd.get_issue_type() == VD::IssueType::NO_ISSUE_DETECTED);
+    CHECK_FALSE(has_missing_voronoi_vertices(poly, vd));
 }
 
 // In this case, the Voronoi vertex (146873, -146873) is included twice.
 // Also, near to those duplicate Voronoi vertices is another Voronoi vertex (146872, -146872).
 // Rotating the polygon will help solve this problem, but then there arise three very close Voronoi vertices.
-// Rotating of the input polygon will help solve this problem.
+// VoronoiDiagram::construct_voronoi repairs it by rotating the input.
 TEST_CASE("Duplicate Voronoi vertices", "[Voronoi]")
 {
     Polygon poly = {
@@ -2095,7 +2122,7 @@ TEST_CASE("Duplicate Voronoi vertices", "[Voronoi]")
     dump_voronoi_to_svg(debug_out_path("voronoi-duplicate-vertices-out.svg").c_str(), vd, Points(), lines);
 #endif
 
-    [[maybe_unused]] auto has_duplicate_vertices = [](const VD &vd) -> bool {
+    auto has_duplicate_vertices = [](const VD &vd) -> bool {
         std::vector<Vec2d> vertices;
         for (const auto &vertex : vd.vertices())
             vertices.emplace_back(Vec2d(vertex.x(), vertex.y()));
@@ -2104,14 +2131,21 @@ TEST_CASE("Duplicate Voronoi vertices", "[Voronoi]")
         return std::unique(vertices.begin(), vertices.end()) != vertices.end();
     };
 
-//    REQUIRE(!has_duplicate_vertices(vd));
+    // Unrepaired, the diagram shows the defect. construct_voronoi detects it and repairs it by
+    // rotating the input.
+    VD raw_vd;
+    raw_vd.construct_voronoi(lines.begin(), lines.end(), false);
+    CHECK(has_duplicate_vertices(raw_vd));
+    CHECK(vd.get_state() == VD::State::REPAIR_SUCCESSFUL);
+    CHECK(vd.get_issue_type() == VD::IssueType::NO_ISSUE_DETECTED);
+    CHECK_FALSE(has_duplicate_vertices(vd));
 }
 
 // In this case, there are three very close Voronoi vertices like in the previous test case after rotation. There is also one
 // missing Voronoi vertex. One infinity-edge (after clip [(146872, -70146871), (146872, -146871)]) passes through this missing
 // Voronoi vertex. This infinite edge [(146872, -70146871), (146872, -146871)] and edge [(146873, -146873), (0, 0)] are intersecting.
 // They intersect probably because the three points are very close to each other, with a combination of the missing Voronoi vertex.
-// Rotating of the input polygon will help solve this problem.
+// VoronoiDiagram::construct_voronoi repairs it by rotating the input.
 TEST_CASE("Intersecting Voronoi edges", "[Voronoi]")
 {
     Polygon poly = {
@@ -2135,7 +2169,7 @@ TEST_CASE("Intersecting Voronoi edges", "[Voronoi]")
     dump_voronoi_to_svg(debug_out_path("voronoi-intersecting-edges-out.svg").c_str(), vd, Points(), lines);
 #endif
 
-    [[maybe_unused]] auto has_intersecting_edges = [](const Polygon &poly, const VD &vd) -> bool {
+    auto has_intersecting_edges = [](const Polygon &poly, const VD &vd) -> bool {
         BoundingBox  bbox         = get_extents(poly);
         const double bbox_dim_max = double(std::max(bbox.size().x(), bbox.size().y()));
 
@@ -2166,5 +2200,12 @@ TEST_CASE("Intersecting Voronoi edges", "[Voronoi]")
         return false;
     };
 
-//    REQUIRE(!has_intersecting_edges(poly, vd));
+    // Unrepaired, the diagram shows the defect. construct_voronoi detects it and repairs it by
+    // rotating the input.
+    VD raw_vd;
+    raw_vd.construct_voronoi(lines.begin(), lines.end(), false);
+    CHECK(has_intersecting_edges(poly, raw_vd));
+    CHECK(vd.get_state() == VD::State::REPAIR_SUCCESSFUL);
+    CHECK(vd.get_issue_type() == VD::IssueType::NO_ISSUE_DETECTED);
+    CHECK_FALSE(has_intersecting_edges(poly, vd));
 }

tests/slic3rutils/test_plugin_capability_config.cpp

@@ -8,6 +8,7 @@
 #include <slic3r/plugin/PythonPluginInterface.hpp>
 
 #include <catch2/catch_test_macros.hpp>
+#include <catch2/catch_message.hpp>
 #include "plugin_test_utils.hpp"
 #include <pybind11/pytypes.h>
 #include <pybind11/eval.h>
@@ -17,6 +18,12 @@
 #include <pybind11/embed.h>
 #include <pybind11/pybind11.h>
 
+#include <boost/filesystem/operations.hpp>
+#include <boost/filesystem/path.hpp>
+
+#include <chrono>
+#include <fstream>
+#include <ios>
 #include <memory>
 #include <string>
 #include <pybind11/cast.h>
@@ -105,6 +112,72 @@ PluginCapabilityId capability_id(PluginCapabilityType type, const char* name, co
     return {type, name, plugin_key};
 }
 
+// restore_config_response looks the capability up in PluginManager, so the restore tests load a real
+// plugin rather than building a detached capability.
+const char* const RESTORE_PLUGIN_KEY = "Restore_Plugin";
+
+const char* const RESTORE_PLUGIN_SOURCE = R"PY(# /// script
+# requires-python = ">=3.12"
+#
+# [tool.orcaslicer.plugin]
+# name = "Restore Plugin"
+# description = "Restore defaults fixture"
+# author = "OrcaSlicer"
+# version = "1.0"
+# type = "script"
+# ///
+import orca
+
+class Target(orca.script.ScriptPluginCapabilityBase):
+    def get_name(self): return "Target"
+    def execute(self, ctx): return orca.ExecutionResult.success()
+    def get_default_config(self): return {"speed": 1}
+
+class Bystander(orca.script.ScriptPluginCapabilityBase):
+    def get_name(self): return "Bystander"
+    def execute(self, ctx): return orca.ExecutionResult.success()
+    def get_default_config(self): return {"speed": 2}
+
+# Loading seeds defaults through get_default_config and fails the plugin if it raises, so this one
+# answers the load and raises from then on.
+class Raising(orca.script.ScriptPluginCapabilityBase):
+    calls = 0
+    def get_name(self): return "Raising"
+    def execute(self, ctx): return orca.ExecutionResult.success()
+    def get_default_config(self):
+        Raising.calls += 1
+        if Raising.calls > 1:
+            raise RuntimeError("boom")
+        return {}
+
+@orca.plugin
+class RestorePackage(orca.base):
+    def register_capabilities(self):
+        orca.register_capability(Target)
+        orca.register_capability(Bystander)
+        orca.register_capability(Raising)
+)PY";
+
+// Writes the restore fixture into {data_dir}/orca_plugins and loads it, returning the load error
+// (empty on success). Call without holding the GIL: the load runs on a worker thread.
+std::string load_restore_plugin(const ScopedDataDir& data_dir_guard)
+{
+    const boost::filesystem::path plugin_dir = data_dir_guard.plugins_dir() / RESTORE_PLUGIN_KEY;
+    boost::filesystem::create_directories(plugin_dir);
+    {
+        std::ofstream out((plugin_dir / (std::string(RESTORE_PLUGIN_KEY) + ".py")).string(), std::ios::binary);
+        out << RESTORE_PLUGIN_SOURCE;
+    }
+
+    PluginManager& manager = PluginManager::instance();
+    manager.discover_plugins(/*async=*/false, /*clear=*/true);
+    manager.load_plugin(RESTORE_PLUGIN_KEY, /*skip_deps=*/true);
+    std::string error;
+    if (!manager.wait_for_plugin_load(RESTORE_PLUGIN_KEY, std::chrono::seconds(120), error) && error.empty())
+        error = "the plugin did not load";
+    return error;
+}
+
 } // namespace
 
 TEST_CASE("Capability config API is exposed on every Python capability", "[PluginConfig][Python]")
@@ -357,26 +430,27 @@ TEST_CASE("Restoring defaults overwrites only the target capability", "[PluginCo
     ScopedPluginManager plugin_system; // declared first: destroyed last
     if (!plugin_system.initialized)
         SKIP("Bundled Python interpreter unavailable: " + PythonInterpreter::instance().last_error());
-    py::gil_scoped_acquire gil; // released before plugin_system's destructor shuts Python down
 
     ScopedDataDir data_dir_guard("plugin-config-py-restore");
     host_config().load();
+    const std::string load_error = load_restore_plugin(data_dir_guard);
+    INFO("load error: " << load_error);
+    REQUIRE(load_error.empty());
 
-    const std::string defaults_body = "    def get_name(self): return 'cap'\n"
-                                      "    def get_default_config(self): return {'speed': 1}\n";
-    py::object target   = make_capability("RestoreTargetCap", defaults_body, "plugin_a", "cap_a");
-    py::object bystander = make_capability("RestoreBystanderCap", defaults_body, "plugin_b", "cap_a");
-
+    const PluginCapabilityId target    = capability_id(PluginCapabilityType::Script, "Target", RESTORE_PLUGIN_KEY);
+    const PluginCapabilityId bystander = capability_id(PluginCapabilityType::Script, "Bystander", RESTORE_PLUGIN_KEY);
     const json edited = json{{"speed", 99}};
-    REQUIRE(py_save_config(target, edited));
-    REQUIRE(py_save_config(bystander, edited));
+    REQUIRE(host_config().store_capability_config(target, edited));
+    REQUIRE(host_config().store_capability_config(bystander, edited));
 
-    // What PluginsDialog::restore_capability_config does: ask the capability, store the answer.
-    auto iface = as_interface(target);
-    REQUIRE(host_config().store_capability_config(capability_id(PluginCapabilityType::Script, "cap_a", "plugin_a"), iface->get_default_config()));
+    const json response = PluginConfig::restore_config_response(target);
 
-    CHECK(host_config().get_config(capability_id(PluginCapabilityType::Script, "cap_a", "plugin_a"))->config == json{{"speed", 1}});
-    CHECK(host_config().get_config(capability_id(PluginCapabilityType::Script, "cap_a", "plugin_b"))->config == json{{"speed", 99}});
+    CHECK(response["ok"] == true);
+    CHECK(response["config"] == json{{"speed", 1}});
+    CHECK(host_config().get_config(target)->config == json{{"speed", 1}});
+    CHECK(host_config().get_config(bystander)->config == edited);
+
+    PluginManager::instance().unload_plugin(RESTORE_PLUGIN_KEY);
 }
 
 TEST_CASE("A raising get_default_config leaves the stored config untouched", "[PluginConfig][Python]")
@@ -384,24 +458,23 @@ TEST_CASE("A raising get_default_config leaves the stored config untouched", "[P
     ScopedPluginManager plugin_system; // declared first: destroyed last
     if (!plugin_system.initialized)
         SKIP("Bundled Python interpreter unavailable: " + PythonInterpreter::instance().last_error());
-    py::gil_scoped_acquire gil; // released before plugin_system's destructor shuts Python down
 
     ScopedDataDir data_dir_guard("plugin-config-py-restore-raise");
     host_config().load();
+    const std::string load_error = load_restore_plugin(data_dir_guard);
+    INFO("load error: " << load_error);
+    REQUIRE(load_error.empty());
 
-    py::object cap = make_capability("RaisingDefaultsCap",
-                                     "    def get_name(self): return 'cap_a'\n"
-                                     "    def get_default_config(self): raise RuntimeError('boom')\n",
-                                     "plugin_a", "cap_a");
+    const PluginCapabilityId raising = capability_id(PluginCapabilityType::Script, "Raising", RESTORE_PLUGIN_KEY);
+    REQUIRE(host_config().store_capability_config(raising, json{{"keep", "me"}}));
 
-    REQUIRE(py_save_config(cap, json{{"keep", "me"}}));
+    const json response = PluginConfig::restore_config_response(raising);
 
-    auto iface = as_interface(cap);
-    REQUIRE(iface);
-    CHECK_THROWS_AS(iface->get_default_config(), py::error_already_set);
+    CHECK(response["ok"] == false);
+    CHECK_FALSE(response["error"].get<std::string>().empty());
+    CHECK(host_config().get_config(raising)->config == json{{"keep", "me"}});
 
-    // The dialog stores nothing when the hook throws: a broken plugin must not wipe user settings.
-    CHECK(host_config().get_config(capability_id(PluginCapabilityType::Script, "cap_a", "plugin_a"))->config == json{{"keep", "me"}});
+    PluginManager::instance().unload_plugin(RESTORE_PLUGIN_KEY);
 }
 
 TEST_CASE("A raising config UI hook surfaces as an exception the host can catch", "[PluginConfig][Python]")

tests/slic3rutils/test_plugin_cloud_metadata.cpp

@@ -76,12 +76,12 @@ TEST_CASE("plugin latest version uses the authoritative catalog field", "[Plugin
 {
     PluginDescriptor descriptor;
     descriptor.version        = "1.3.0";
-    descriptor.latest_version = "1.3.0";
+    descriptor.latest_version = "1.4.0";
     PluginChangelog changelog;
     changelog.version = "1.2.0";
     descriptor.changelog.push_back(changelog);
 
-    CHECK(descriptor.latest_available_version() == "1.3.0");
+    CHECK(descriptor.latest_available_version() == "1.4.0");
 }
 
 TEST_CASE("plugin latest version falls back to the descriptor version", "[PluginDescriptor]")

tests/slic3rutils/test_plugin_lifecycle.cpp

@@ -615,8 +615,22 @@ TEST_CASE("Python module release removes package submodules and owned sys.path",
 
     // Ensure the next import executes the new submodule rather than reusing a stale package child.
     write_package("'new'");
-    boost::system::error_code ec;
-    fs::remove_all(package_root / "__pycache__", ec);
+    {
+        // The rewrite can keep the old mtime and size, so drop the bytecode wherever the
+        // interpreter caches it.
+        PythonGILState gil;
+        REQUIRE(gil);
+        PyObjectPtr util(PyImport_ImportModule("importlib.util"));
+        REQUIRE(util);
+        for (const char* file : {"__init__.py", "sub.py"}) {
+            PyObjectPtr source(PyUnicode_DecodeFSDefault((package_root / file).string().c_str()));
+            REQUIRE(source);
+            PyObjectPtr cached(PyObject_CallMethod(util.get(), "cache_from_source", "O", source.get()));
+            REQUIRE(cached);
+            boost::system::error_code ec;
+            fs::remove(fs::path(PyUnicode_AsUTF8(cached.get())), ec);
+        }
+    }
 
     paths.clear();
     modules.clear();

tests/slic3rutils/test_slicing_pipeline_bindings.cpp

@@ -615,12 +615,19 @@ TEST_CASE("orca.host: SurfaceCollection.set mutates geometry; lslices via make_s
                     .attr("expolygon").attr("contour").attr("as_array")().cast<py::array>();
     CHECK(c.shape(0) == 4);
 
-    // lslices are derived: make_slices() re-derives them + refreshes the bbox cache.
+    // lslices are derived: make_slices() re-derives them from the region slices and refreshes the
+    // bbox cache.
     TestLayer layer;
+    layer.add_region(nullptr);
     py::object ly = py::cast(static_cast<Slic3r::Layer*>(&layer), py::return_value_policy::reference);
-    // (A hand-built layer has no regions, so make_slices() yields empty lslices — still null-safe.)
+    ly.attr("regions")().cast<py::list>()[0].attr("slices").attr("set")(expolys, ST.attr("stInternalSolid"));
+    REQUIRE(layer.lslices.empty());
     ly.attr("make_slices")();
-    CHECK(layer.lslices_bboxes.size() == layer.lslices.size());
+    REQUIRE(layer.lslices.size() == 1);
+    CHECK_THAT(layer.lslices.front().area(), WithinRel((double) s * (double) s, 1e-9));
+    REQUIRE(layer.lslices_bboxes.size() == 1);
+    CHECK(layer.lslices_bboxes.front().min == Point(0, 0));
+    CHECK(layer.lslices_bboxes.front().max == Point(s, s));
 }
 
 TEST_CASE("orca.host ExPolygon in-place transforms + SurfaceCollection.append (sample ops)", "[slicing_pipeline]") {