Tests: move tests from USD test directory into `io/common` and `io/usd`

This commit is a followup of {D7649}, and ports the USD tests to the new
testing approach. It moves test code from `tests/gtests/usd` into
`source/blender/io/common` and `source/blender/io/usd`, and adjusts the
use of namespaces to be consistent with the other tests.

I decided to put one test into `io/usd/tests`, instead of
`io/usd/intern`. The reason is that this test does not correspond with a
single file in that directory; instead, it tests Blender's integration
with the USD library itself.

There are two new CLI arguments for the Big Test Runner:

- `--test-assets-dir`, which points to the `lib/tests` directory in the
  SVN repository. This allows unit tests to find test assets.
- `--test-release-dir`, which points to `bin/{BLENDER_VERSION}` in the
  build directory. At the moment this is only used by the USD test.

The CLI arguments are automatically passed to the Big Test Runner when
using `ctest`. When manually running the tests, the arguments are only
required when there is a test run that needs them.

For more info about splitting some code into 'common', see
rB084c5d6c7e2cf8.

No functional changes to the tests themselves, only to the way they are
built & run.

Differential Revision: https://developer.blender.org/D8314

Reviewed by: brecht, mont29

1 files changed, 6 insertions, 1 deletions

diff --git a/tests/gtests/runner/CMakeLists.txt b/tests/gtests/runner/CMakeLists.txt
index e7cbabfe7c6..7f28ede9ae9 100644
--- a/tests/gtests/runner/CMakeLists.txt
+++ b/tests/gtests/runner/CMakeLists.txt
@@ -60,4 +60,9 @@ setup_liblinks(blender_test)
 # exposes those tests individually to the ctest runner.
 # See https://cmake.org/cmake/help/v3.18/module/GoogleTest.html
 include(GoogleTest)
-gtest_discover_tests(blender_test)
+gtest_discover_tests(blender_test
+  # So that unit tests know where to find files:
+  EXTRA_ARGS
+    --test-assets-dir "${CMAKE_SOURCE_DIR}/../lib/tests"
+    --test-release-dir "$<TARGET_FILE_DIR:blender>/${BLENDER_VERSION}"
+)