Build and run a test in CI (#10835)

* Actually build tests on Linux and allow RelWithDebInfo

They weren't being built.

Also cleaned up --config flags which enables RelWithDebInfo on Linux,
now that Ninja Multi-Config is used, it's quite trivial.

* Remove obsolete Slic3r Perl tests

The directory doesn't exist, they're already gone.

* Add GH job for running unit tests

* Move unit test execution to script and upload test results

* Don't run scheduled builds on forks

* Only deploy from SoftFever/OrcaSlicer

Will stop failures on forks

* Use artifact instead of cache

* Tweak archive and checkout paths

Keep getting error:

```
/home/runner/work/_temp/902d0a0a-6d23-4fe0-a643-8b5cc4efd25b.sh: line 1: scripts/run_unit_tests.sh: Permission denied
```

That seems to be because I didn't use actions/checkout, the working
directory is never setup correctly? So using checkout to get scripts
directory. Unsure if archive will preserve the `build/tests/` prefix;
will find out soon.

* Use tar to package directory and write results to correct directory

Tar preserves filenames and directory structure

* Use tar -xvf not -xzf

Muscle memory failed me

* Add testing wiki page

* Save test logs on failure and choose correct directory for junit

* Consolidate apt install steps, use for unit tests too, disable non-Linux builds

Temporarily disable non-Linux builds to save time while developing
this.

Cache the apt packages to save some time searching apt and downloading
them again (though I realize this is also downloading, but hopefully
by something closer and faster).

Remove all the redundant packages listed in the workflow and debian
distribution lists.

* Remove apt install steps from workflow

`./build-linux.sh -u` is supposed to install all needed packages, so
it should build without needing anything besides that. If I'm wrong
this commit will be dropped.

* Need composite action checked out locally

* Re-enable non-Linux builds now that it's working

* Skip a deploy and a notarize in forks

They only succeed in the main repo.

* Fix multi-build for non-Release builds: share CONFIG

* Correct build errors in unit tests

Indeterminate method signatures resolved. Updated script to build all
the tests.

* Fix -g vs -e for RelWithDebInfo

* Change CONFIG->BUILD_CONFIG

Missed one in prior commits

* Reduce wasteful redundant build artifact copies

1. Don't copy the artifacts and leave them; make a hard link first;
only make a copy only while creating AppImage.

2. Don't tar up the `package` directory; nothing uses this tar AFAICT

* Fix directory name

* Change jigsaw auth test URLs to httpbin.org

No idea why the basic auth doesn't work, but it doesn't work for
`curl` CLI either. This does.

* Remove force-build

It got reverted at
e3f049829b
for unknown reasons.

* Add timeout for unit tests in GitHub Actions workflow (#11146)

---------

Co-authored-by: SoftFever <softfeverever@gmail.com>

doc/developer-reference/How-to-build.md

@@ -279,9 +279,9 @@ The build system supports multiple Linux distributions including Ubuntu/Debian a
    ./build_linux.sh -d
    ```
 
-3. **Build OrcaSlicer:**
+3. **Build OrcaSlicer with tests:**
    ```shell
-   ./build_linux.sh -s
+   ./build_linux.sh -st
    ```
 
 4. **Build AppImage (optional):**
@@ -291,14 +291,15 @@ The build system supports multiple Linux distributions including Ubuntu/Debian a
 
 5. **All-in-one build (recommended):**
    ```shell
-   ./build_linux.sh -dsi
+   ./build_linux.sh -dsti
    ```
 
 **Additional build options:**
 
-- `-b`: Build in debug mode
+- `-b`: Build in debug mode (mostly broken at runtime for a long time; avoid unless you want to be fixing failed assertions)
 - `-c`: Force a clean build
 - `-C`: Enable ANSI-colored compile output (GNU/Clang only)
+- `-e`: Build RelWithDebInfo (release + symbols)
 - `-j N`: Limit builds to N cores (useful for low-memory systems)
 - `-1`: Limit builds to one core
 - `-l`: Use Clang instead of GCC
@@ -309,10 +310,14 @@ The build system supports multiple Linux distributions including Ubuntu/Debian a
 > The build script automatically detects your Linux distribution and uses the appropriate package manager (apt, pacman) to install dependencies.
 
 > [!TIP]
-> For first-time builds, use `./build_linux.sh -u` to install dependencies, then `./build_linux.sh -dsi` to build everything.
+> For first-time builds, use `./build_linux.sh -u` to install dependencies, then `./build_linux.sh -dsti` to build everything.
 
 > [!WARNING]
-> If you encounter memory issues during compilation, use `-j 1` or `-1` to limit parallel compilation, or `-r` to skip memory checks.
+> If you encounter memory issues during compilation, use `-j 1` or `-1` to limit parallel compilation and `-r` to skip memory checks.
+
+#### Unit Testing
+
+See [How to Test](How-to-test) for more details.
 
 ---
 

doc/developer-reference/How-to-test.md

@@ -0,0 +1,27 @@
+# How to Test
+
+This wiki page describes how to build and run tests on Linux. It should eventually provide guidance on how to add tests for a new feature.
+
+## Build Tests
+
+Can be built when you are building Orca Slicer binary by including the `-t` flag for `build_linux.sh`:
+
+```
+build_linux.sh -st
+```
+
+Test binaries will then appear under `build/tests`. As of this writing, not all tests will be built.
+
+## Run Unit Tests
+
+### Run All
+
+```
+ctest --test-dir build/tests
+```
+
+### Run a Specific Set
+
+```
+ctest --test-dir build/tests/slic3rutils
+```