Defend against console mocks in TAP reporter

[Krinkle]

Test case

QUnit.module( "e2e/cli", function() {
	QUnit.test( "help", function( assert ) {
		var cli = function () {};
		return cli( "help" ).then( ( data ) => {
			assert.strictEqual( data, true, 'data' );
		} );
	} );
} );

What actually happened?

qunit  test/
TAP version 13
ok 1 Writer > constructor()
ok 2 Writer > child()
ok 3 Writer > prefix()
ok 4 e2e/cli > record
ok 5 e2e/cli > compare
ok 7 e2e/cli > unknown command
ok 8 e2e/conductor > record() - clean state per run
ok 9 conductor > expandScenario()
ok 10 util/is > like() - single type
ok 11 util/is > like() - multi type
ok 12 util/is > like() - plain object
1..12
# pass 11
# skip 0
# todo 0
# fail 1

Notes

Note how there is nothing in the output other than fail 1. After I debugged the whole thing and realised that cli() didn't return a promise (Cannot read property 'then' of undefined"), I did notice there is a tiny little clue.

The clue is, number 6 is skipped in the output (it goes from 5 to 7). So in retrospect, I could've used that to find which test the problem is with, and maybe from there find out what the problem is.

Initially, though, I didn't even know where it was coming from.

[Krinkle]

In trying to make a test case, I found that error handling generally does actually work fine.

The problem was that in my specific test case, there was an active mock for the global console object. Specifically, it was a mock applied/removed from hooks.before and hooks.after.

Mocking the object from beforeEach/afterEach works fine.

[trentmwillis]

Perhaps we should save off references to the original functions in the logger?

[Krinkle]

@trentmwillis Yeah, something like that.

I haven't tried fixing it yet, but I assumed we'd have to do the ref-saving in js-reporters/TapReporter, rather than in qunit. But.. maybe we need both?

[trentmwillis]

Ah yes, that is correct. We should do it in both locations.

[Krinkle]

Continuing at qunitjs/js-reporters#125.