Ported test_config.cpp from upstream Slic3r.

Extended ConfigBase with set() functions similar to the upstream Slic3r.
ConfigBase::set_deserialize() newly throws if the operation fails.
Extrusion width parameters are newly tested for negative values.

src/libslic3r/PrintConfig.cpp

@@ -433,6 +433,7 @@ void PrintConfigDef::init_fff_params()
                    "If left zero, default extrusion width will be used if set, otherwise 1.125 x nozzle diameter will be used. "
                    "If expressed as percentage (for example 200%), it will be computed over layer height.");
     def->sidetext = L("mm or %");
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
@@ -541,6 +542,7 @@ void PrintConfigDef::init_fff_params()
                    "(see the tooltips for perimeter extrusion width, infill extrusion width etc). "
                    "If expressed as percentage (for example: 230%), it will be computed over layer height.");
     def->sidetext = L("mm or %");
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
@@ -863,6 +865,7 @@ void PrintConfigDef::init_fff_params()
                    "If set to zero, it will use the default extrusion width.");
     def->sidetext = L("mm or %");
     def->ratio_over = "first_layer_height";
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(200, true));
 
@@ -994,6 +997,7 @@ void PrintConfigDef::init_fff_params()
                    "You may want to use fatter extrudates to speed up the infill and make your parts stronger. "
                    "If expressed as percentage (for example 90%) it will be computed over layer height.");
     def->sidetext = L("mm or %");
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
@@ -1406,6 +1410,7 @@ void PrintConfigDef::init_fff_params()
                    "If expressed as percentage (for example 200%) it will be computed over layer height.");
     def->sidetext = L("mm or %");
     def->aliases = { "perimeters_extrusion_width" };
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
@@ -1743,6 +1748,7 @@ void PrintConfigDef::init_fff_params()
                    "If left zero, default extrusion width will be used if set, otherwise 1.125 x nozzle diameter will be used. "
                    "If expressed as percentage (for example 90%) it will be computed over layer height.");
     def->sidetext = L("mm or %");
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
@@ -1917,6 +1923,7 @@ void PrintConfigDef::init_fff_params()
                    "If left zero, default extrusion width will be used if set, otherwise nozzle diameter will be used. "
                    "If expressed as percentage (for example 90%) it will be computed over layer height.");
     def->sidetext = L("mm or %");
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
@@ -2076,6 +2083,7 @@ void PrintConfigDef::init_fff_params()
                    "If left zero, default extrusion width will be used if set, otherwise nozzle diameter will be used. "
                    "If expressed as percentage (for example 90%) it will be computed over layer height.");
     def->sidetext = L("mm or %");
+    def->min = 0;
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(0, false));