Record statistics on which test covers which condition

[rillig]

Assuming that gobco would output which test covers which condition, it would be possible to answer questions like the following:

• For each testee, is there a test that covers all branches of that testee? (minimal unit tests)
• Which tests are necessary to get 100% branch coverage for a given testee?

Implementation ideas:

• Have an additional list of test names for each condition, possibly indirectly by mapping the test name to an int for performance.
• Extend the gobco JSON output with this list of tests.

[visu-suganya]

Hi @rillig

Current implementation outputs the condition details of which are covered and not covered.

• example:

  if(a>0 && a<100) {
  print "something"
  }

  gobco gives output as 4 (true and false)branches for 2 conditions(a>0 and a<100) like below in json output

  {
  "Start": "file.go:30:4",
  "Code": "a>0",
  "TrueCount": 2,
  "FalseCount": 0
  },
  {
  "Start": "file.go:30:11",
  "Code": "a<100",
  "TrueCount": 1,
  "FalseCount": 2
  },

  Can I find branch coverage (not condition coverage) from your output?

Please help me to find whether edge cases are covered or not?

[rillig]

Hi @visu-suganya, as you already guessed, gobco does not really provide branch coverage but instead condition coverage, despite its name. Up to now, I didn't need branch coverage, as I could tell from the missing conditions what parts of the code are still uncovered. Do you actually need the branch coverage, or is it merely a feeling of "the program is named gobco, so it should report branch coverage"? What use case do you have that requires branch coverage but not condition coverage?

[visu-suganya]

@rillig Thanks for the immediate reply. I need branch coverage result so that developers can easily fix when compared to condition coverage.

In branch coverage, only 2 outcomes totally but in condition coverage, need to cover all the 4 outcomes(it will be difficult to cover all in development period). So Firstly I need to achieve branch coverage as first step and then go for condition.

[visu-suganya]

Hi @rillig Is there any possibility to get C1(branch coverage) output?

[rillig]

To get C1 output, you can change the method instrumenter.markConds by removing the branches for *ast.UnaryExpr and *ast.BinaryExpr. If that generates the output that you expect, I'll include it in the next release.

[visu-suganya]

@rillig Thanks for the implementation and please release the implemented feature so that I can use it. Thanks a lot.

[rillig]

I don't have plans to add this feature anymore. In the past few years I didn't have a need for it.

The comments on this issue are generally off-topic, they are not about finding out which tests cover which code, but about implementing branch coverage in addition to condition coverage.