how can I know which assertion failed ?

[mderazon]

Hi guys, don't know if it's a Chai question / Mocha, but I am facing a very basic issue that I feel like i'm missing something.

Some of my tests have more than a few assertions and when some of them fail all I get is something like AssertionError: expected true to be false.

Is there any way to know which assertion failed ? Line number / stack trace perhaps ?

I know I can add a text description to each assertion but I don't want to clutter my test files with unnecessary text just to mark which assertion failed when a line number would be sufficient.

Right now I am just commenting out assertion and re-running tests just to find the faulty one. I feel stupid when I do that...

Thanks 👍

[mderazon]

possible duplicate of #377

[keithamus]

Hey @mderazon thanks for the issue.

Mocha should present you with a stack trace of the error, including the line which threw the assertion error.

Could you please paste the output of both your tests, and the failing log - and if it does not give you a stack trace I'll hopefully be able to point you as to why not.

[mderazon]

Thanks

I actually do see that in some cases Mocha gives me a line number (greyed out below the assertion).
For example when running the assertion

expect(res.body.code).to.equal('something');

I get

AssertionError: expected 'success' to equal 'something'
      + expected - actual

      +"something"
      -"success"

      at Context.<anonymous> (order-test.js:239:30)

But in other cases when I run for example the assertion

expect(res.body.data.user.can_buy).to.be.true;

I simply get

1) should charge successfully


  0 passing (8s)
  1 failing

  1) charge should charge successfully:
     AssertionError: expected false to be true

[keithamus]

@mderazon what happens if you set chai.config.includeStack = true; at the top of the file?

[mderazon]

@keithamus it shows the stack!

Is there any reason why this shouldn't be the default behaviour ?

[keithamus]

Honestly, I don't know. I'm sure there is a good reason. @logicalparadox may be able to tell you.

[diversario]

I upgraded to chai 2.x and node v0.12.x and now I don't get stack traces anymore, even with chai.config.includeStack = true.

[keithamus]

@diversario what test runner are you using? What versions? Do you have some sample code? It might be better to file a new issue.

[j13z]

@diversario: Which mocha version do you use? I figured out that I don’t get proper stack traces anymore for any version > 2.2.1 (thought it was Chai first, but it’s not). See mochajs/mocha#1736

[diversario]

That might be it; I upgraded to mocha 2.2.5.

[j13z]

@diversario Try the --full-trace option (see mochajs/mocha#1736, updated).

[meeber]

Seems this has been resolved but let us know if otherwise.