Add metadata to TestCase

[bryanbcook]

This PR introduces a meta_data property to TestCase as outlined in proposal #34

All existing unit tests have been updated to support the new property.

• Cucumber implementation
• jUnit implementation
• Mocha implementation
• TestNG implementation
• xUnit implementation

[bryanbcook]

I started the TestNG implementation for mapping <groups> to individual <test-method>, but shelved it when I realized it might need a deeper review of that parser.

The mapping should be trivial: iterate over the groups and build a Map<string,string[]> between each method signature and its associated list of groups. However, the current testng parser implementation strips out the <class> when locating relevant <test-method> nodes.

const rawClasses = rawTest.class;
for (let j = 0; j < rawClasses.length; j++) {
  rawTestMethods.push(...rawClasses[j]['test-method'].filter(raw => !raw['@_is-config']));
}

I also wasn't sure which tests were exercising the getTestSuite versus getTestSuiteFromTests.

Any suggestions?

[bryanbcook]

I was able to address the testng issue by propagating the className into the test-method for easy retrieval.

[ASaiAnudeep]

@bryanbcook Thank you for your comprehensive research on all the test result formats. Contributions like yours will make our project stronger and more reliable.

[bryanbcook]

@ASaiAnudeep - what are your thoughts on preserving the original tags?

[bryanbcook]

If you're ok with this, please use the 'squash and merge' option when completing the pull-request.