Mocha: Hook failures change the shape of the test suite

[cowboyd]

If a beforeEach hook fails, then all subsequent tests in a suite and all sub-suites are not run. For example:

// hook-test.js
describe("outer context", function() {
  beforeEach(function() {
    throw new Error("this is a failure in a before each hook");
  });
  it("reports the first assertion", function() {

  });
  it("does not report the existence of this test case", function() {

  });
  describe("inner context", function() {
    it("does not report report its existence in the output", function() {

    });
  });

});

reports only a single testcase, even though there are three defined:

$ mocha --reporter min hook-test.js
0 passing (6ms)
  1 failing

  1) outer context "before each" hook for "reports the first assertion":
     Error: this is a failure in a before each hook
      at Context.<anonymous> (test/mocha-test.js:3:11)

As outlined in #1043, this is the intended behavior for both beforeEach as well as other hooks. This makes sense from an efficiency prespective; after all, there is no point in actually running the testcases when it is assured that they are going to fail.

The problem with this is that when you're refactoring a large codebase, or doing something like upgrading an underlying library, or rehabilitating a codebase that has allowed its test suite to get out o sync.... work that might take days or weeks, this behavior alters _how many total testcases are reported_. So as you make changes, the reporting varies widely. We've seen the pass/total numbers of test cases jump from 95/220, to 4/8, then down to 0/1 in the case of a global hook failure, then back up to 35/160 in a matter of minutes.

This can be very disorienting, and it obscures your overall progress towards your goal which is a completely green suite where all tests are passing. The fact that a test is not run, does not mean that it doesn't exist, and that it is not important.

Rather than exclude a test completely from the output, it makes more sense to not run it, but still report it as a failure. That way, the shape of the test suite remains constant. If I have 225 testcases, then that's what I have, even if only 26 of them are passing. I at least know that I'm 12% there, which test suites are related by the same failure, and I can track total progress.

If this makes sense, it would be something I'd be happy to help implement.

[cowboyd]

Any thoughts on this? I'm cc/ing @travisjeffery @boneskull and @danielstjules since you all seem to be most active in the issues.

As mentioned, I'd be willing to take a stab at implementing this if I thought that the PR were likely to be accepted. Cheers!

[travisjeffery]

if the code to implement the fix isn't too crazy i'd likely accept it

[cletusw]

I'm also experiencing this. I work around it by running mocha programmatically, and manually marking any tests that match my current grep but have no state set as failed.

[parxier]

@cletusw can you please post an example on how you:

• run mocha programmatically
• interpret and enrich results (set state as failed)

[cletusw]

I use my own mocha-parallel-js library (runner.js is the part that runs Mocha) then do the following to get it in the format that I want:

var tests = [];
// rootSuite is from Mocha
if (rootSuite.suites) {
  // grep is provided by the user and also passed to Mocha
  var userGrep = new RegExp(grep);
  tests = flatten(rootSuite).filter(function (test) {
    // Remove tests that didn't run because of a grep
    return userGrep.test(test.fullTitle);
  });

  tests.forEach(function (test) {
    // When a beforeEach fails, mocha skips the remaining tests in the
    // suite but doesn't mark them as failed, which makes the PASS/FAIL
    // numbers weird. If a non-pending, grep-matching test didn't run, we
    // just mark it as failed.
    test.pending || test.state || (test.state = 'failed');
  });
}

function flatten(suite) {
  suite.fullTitle = ((suite.parent && suite.parent.title) ? (suite.parent.title + ' ') : '') + suite.title;
  suite.topSuiteTitle = (suite.parent && suite.parent.topSuiteTitle) ? suite.parent.topSuiteTitle : suite.title;
  if (suite.tests) {
    suite.tests.forEach(function(test) {
      test.fullTitle = suite.fullTitle + ' ' + test.title;
      test.topSuiteTitle = suite.topSuiteTitle;
    });
  }
  return suite.suites.map(flatten).reduce(function (a, b) {
    return a.concat(b);
  }, suite.tests || []);
}

[cletusw]

@cowboyd Are you working on this by any chance? This is a huge problem for us and I'd really like to remove the hack I noted above.

[mekdev]

Hi guys, I would second the priority of this also.
This is causing inconsistent results for us. We also wrote a custom reporter to mark the whole suite as need investigation since a beforeEach() hook failure will mean some tests are missing from the result.

[cowboyd]

@cletusw I'm not working on this no. It's in that category of papercuts that we're willing to cope with because the solution seems like a lot of work. I'd be willing to collaborate, pair program etc.. , but can't take the lead implementing this directly.

[boneskull]

Haven't got a chance to look at this. doesn't sound too bad, unless the reporters wouldn't understand.

[nlundquist]

Even if this required changes to reporters it would be worthwhile

[shridharkalagi]

Any update on this issue? I'm also facing the similar problem

[vinczedani]

We are also having the same issue, for us it would be logical to see the test cases as failed if the before or beforeEach hook fails, now they just disappear