[Build] Fix incorrect Version metadata in dist-info

Closes #123.

The CMake script has the ability to simulate a Python package
installation, such that a `dist-info` metadata directory is installed
alongside the package, effectively preventing accidental overwrite by
other package managers (e.g. pip) when the project is installed via
CMake - see #58.

However, the `Version` field in the `METADATA` file that forms part
of the Python package `dist-info` was not being properly filled in.

This was not caught by CI because the test for it is only enabled if
generation of Python traits via CMake is enabled (i.e.
`OPENASSETIO_MEDIACREATION_GENERATE_PYTHON`), which was not the case
for the "test" CMake preset used by the "Test Cpp" CI job.

There was another problem with running the test, in that the PYTHONPATH
was not properly set in the CMake test target, and so the test would not
necessarily be able to locate the `openassetio-mediacreation` package
installed by CMake.

Signed-off-by: David Feltell <david.feltell@foundry.com>

Author: feltech

.github/workflows/test.yml

@@ -46,6 +46,9 @@ jobs:
       - name: Install Traitgen
         run: python -m pip install openassetio-traitgen
 
+      - name: Install Python test dependencies
+        run: python -m pip install -r tests/python/requirements.txt
+
       - name: Configure CMake build
         run: |
           cmake -S . -DCMAKE_PREFIX_PATH=$(pwd)/openassetio -B build -G Ninja --preset test

CMakePresets.json

@@ -7,7 +7,8 @@
                 "dev": true
             },
             "cacheVariables": {
-                "OPENASSETIO_MEDIACREATION_ENABLE_TEST": "ON"
+                "OPENASSETIO_MEDIACREATION_ENABLE_TEST": "ON",
+                "OPENASSETIO_MEDIACREATION_GENERATE_PYTHON": "ON"
             }
         }
     ]

cmake/packaging/python.dist-info/METADATA.in

@@ -1,3 +1,3 @@
 Metadata-Version: 2.1
 Name: openassetio-mediacreation
-Version: @OPENASSETIO_MEDIACREATION_PYTHON_PACKAGE_VERSION@
+Version: @OPENASSETIO_MEDIACREATION_PYTHON_PKG_VERSION@

tests/cpp/CMakeLists.txt

@@ -17,17 +17,13 @@ target_compile_features(test.cpp PRIVATE cxx_std_17)
 
 if (OPENASSETIO_MEDIACREATION_ENABLE_PYTHON_INSTALL_DIST_INFO)
 
-    # Build the command to extend the PYTHONPATH such that the
-    # site-packages directory in the install tree is included correctly.
-    set(_set_pythonpath_command
-        PYTHONPATH=${CMAKE_INSTALL_PREFIX}/${OPENASSETIO_MEDIACREATION_PYTHON_SITEDIR})
-
     # Add pytest target to run the packaging tests. These are concerned
     # with python metadata information so run in a python context.
     add_custom_target(
         openassetio-mediacreation.tests.packaging
         COMMAND cmake -E echo -- "Running pytest check for CMake dist-info packaging"
-        COMMAND ${_set_pythonpath_command} &&
+        COMMAND ${CMAKE_COMMAND} -E env
+        PYTHONPATH=${CMAKE_INSTALL_PREFIX}/${OPENASSETIO_MEDIACREATION_PYTHON_SITEDIR}
         pytest -v --capture=tee-sys
         "${CMAKE_CURRENT_LIST_DIR}/test_cmake.py"
         WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"