Fix broken test: Mock runFunc and add assertions to FFmpegGetInfoTest

[Euklios]

PR #256 added a static reference that cannot be resolved unless we run on a specific environment. Additionally, the runFunc has not been mocked, resulting in an actual call to the FFmpeg executable.

I have applied the following modifications:

• Mock load the regular mocks for ffmpeg -version and ffmpeg -codecs.
• Break after each case (the old syntax would otherwise fall through and add to all consecutive lists)
• Add a dataCodecs list and another codecs list (the second one should always be empty unless FFmpeg adds another CodecType)
• Add assertions for the size of each collection and assert the existence of at least one element within it