tests: update Events/07 test to clarify interpretation of tag end slashes

[vassudanagunta]

This PR contains suggested enhancements to the Events/07-self-closing.json test.

It also suggests a testing strategy that can be applied in other cases: a set of tests where the input and context are identical except for one isolated change. The outputs can thereby be diffed, showing the effect of the isolated change.

No worries if this isn't merged. Also happy to make any changes desired changes.

Test 07 enhancements

The original 07-self-closing.json covered two cases:

• a tag ending in /> but where the / is in fact part of the attribute value -- thus not a self-closing tag

• an HTML void element, <hr>, in XHTML self-closing style.

  One flaw with this test is that hr is also a void element: While the test passes because the expected closetag event occurs, one doesn't know if it occurs because of the end slash or because it is a void element.

  The test 07-self-closing.json only included a self-closing tag for a void element. This made the test ambiguous in purpose if you didn't know that htmlparser2 followed the above distinction.

The new 07a to 07h tests cover much more:

• base name for all these tests is "end slash" rather than "self-closing" because what's being tested is how that end slash is interpreted in different contexts, e.g. as the mark of a self-closing tag, a part of the attribute, or ignored entirely.

• each of the 8 tests represents one isolated change compared to one or more of the others:

  • void vs non-void
  • with and without end slash
  • xmlMode off vs on
  • recognizeSelfClosing off vs on
  • end slash attached to unquoted attribute value

  This allows one to diff the event streams to see the effect of that isolated change. For example, you can compare:

  • 07a with 07d to see that <hr/> generates a closetag event while <xx/> does not. The former is a void element and the latter is not.
  • 07x with 07y to see the effect of xmlMode.

recognizeSelfClosing test coverage and test demonstrated semantics

This option was introduced in #74 but without any tests nor any documentation.

I confirmed there is no test coverage by:

1. Temporarily adding the following line to Parser.ts's constructor:

   this.options.recognizeSelfClosing = !this.options.recognizeSelfClosing
   

2. Ran the tests. No tests failed. The above change inverted the option for every test, and would have caused any test covering this option to fail.

I added coverage via case 07f

There is no clear documentation on the semantics of recognizeSelfClosing, but based on the new 07 tests and diffing their outputs, I was able to surmise the following:

🌶 recognizeSelfClosing really means "recognized all tags ending with /> as self-closing in normal HTML mode (as if in xmlMode), not just void element tags"

[coveralls]

Pull Request Test Coverage Report for Build 1594386588

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 99.46%

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Totals
Change from base Build 1592764720:	0.0%
Covered Lines:	737
Relevant Lines:	741

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💛 - Coveralls

[fb55]

Hi @vassudanagunta, thanks for the great description, and you're completely right with your interpretation. Good catch on recognizeSelfClosing not being tested.

There is currently a linting issue (npm run lint will show it) — once that's fixed, I'm happy to merge this.

[vassudanagunta]

No problem! I was evaluating htmlparser2 for a project of mine, a library that I also intend to publish for open source public consumption. I love your parse event-based test framework... If I have any question about how htmlparser2 works, all i have to do is create a simple JSON file with the input and config. Or copy an existing one and make one isolated change to see the behavior diff. Well done!

[fb55]

Thanks @vassudanagunta