[ChromeOS] find a way to exclude specific tests when using a globbing pattern

[a-wai]

In multiple test jobs, we use a globbing pattern in order to execute all tests matching this pattern; for example, video.PlatformDecoding.v4l2_stateless_h264_* is (internally) expanded by tast to execute the following tests:

• video.PlatformDecoding.v4l2_stateless_h264_baseline
• video.PlatformDecoding.v4l2_stateless_h264_main

However, there are cases where a few tests matched by the pattern are expected to fail, for example:

• video.ChromeStackDecoderVerification.vp9_0_svc (matched by video.ChromeStackDecoderVerification.*)
• video.PlatformDecoding.v4l2_stateful_vp9_0_group4_sub8x8_sf (matched by video.PlatformDecoding.v4l2_stateful_vp9_0_group4_*)

Excluding those tests would currently require manually listing individual tests instead of using the globbing pattern, which causes the following issues:

• this will significantly increase the configuration files size
• we will likely miss tests introduced in future CrOS versions, which would otherwise be automatically matched by the globbing pattern

As a consequence, it could be interesting to find a way to exclude known-failing tests while still keeping the globbing pattern.

Note: this is a ChromeOS-specific counterpart to #2483

[a-wai]

It seems tast developers did think about this already and provided the -testfilterfile command-line option, allowing one to list specific tests to be ignored. The file is a simple text file, listing one test per line (prefixed with -) and allowing comments in shell style.

For example, we could dynamically create the following file:

# Disabled tests for KernelCI
-video.ChromeStackDecoderVerification.vp9_0_svc

This would disable the video.ChromeStackDecoderVerification.vp9_0_svc even if it is matched by the globbing pattern used in the tast-decode-chromestack job definition.

Example: manually-altered LAVA job showing the exclude file being created and the video.PlatformDecoding.v4l2_stateful_vp9_0_group4_sub8x8_sf test being skipped as expected