Test failures are not properly reported

[Marcono1234]

Version
Extension Version: 1.4.3
CodeQL CLI Version: 2.4.4

Describe the bug
It appears the VSCode extension invokes CodeQL CLI with --format jsonz. With that format only a small portion of the information is written to stdout, most of the information is inside the JSON data. With #626 some of the JSON data is read, but apparently not all. Most notably, the extension is apparently not reading failureDescription.

This makes understanding test failures pretty difficult, for example when no .expected file exists (see also github/codeql#5343).

To Reproduce

1. Clone https://github.com/github/codeql
2. Delete cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/annotate_sinks_only/remote-flow-sink.expected
3. Run only the corresponding test file remote-flow-sink.ql from the "Test" tab of VSCode
   ❌ The output only says (roughly)

   0 tests passed; 1 tests failed:
   FAILED: path/to/test.ql
   failed: path/to/test.ql
   Query produced no results.

Expected behavior
The VSCode extension should evaluate the failureDescription, if present, (and maybe more members of the JSON data) of the test result and inform the user.

[aeisenberg]

Thanks for raising this issue. I see how this could have clarified things on github/codeql#5343.

[Marcono1234]

I was mostly writing this from the perspective of InlineExpectationsTest which has empty .actual and .expected files, but it appears for tests with a non-empty .actual file, even when the .expected file is missing (and a failureDescription is present), it still generates useful diff results. So maybe the failureDescription should be evaluated in addition to diff?

[Marcono1234]

Has been fixed by #788; in version 1.4.4 of the extension the missing .expected file is now correctly reported.