What's the best way to use testdouble.js with tape?

[d6u]

I saw #33 but it's quite verbose to use testdouble with tape:

const test = require('tape');
const td = require('testdouble');

test('verify invoked', function(t) {
  t.plan(1)

  var stub = td.create()

  stub('any arguments', 0, 1, 2)

  t.doesNotThrow(function() {
    td.verify(stub0())
  }, 'called with more arguments when none are specified')
})

Anyway to not pass a callback to t.doesNotThrow?

Thanks!

[searls]

Forgive my naivety, but what does tape do when a function passed to test throws an error? I presume it fails the test, right? If so, why not:

const test = require('tape');
const td = require('testdouble');

test('verify invoked', function(t) {
  t.plan(1)

  var stub = td.create()

  stub('any arguments', 0, 1, 2)

  td.verify(stub())
})

[d6u]

@searls Because we called t.plan(1), tape expect have one assertion method called, which was t.doesNotThrow. Since we are not calling assertion in your example, tape will complaint about it. The rest should work though.

[Schoonology]

@d6u, can you use t.end() at the end of your test in lieu of using t.plan() at the beginning?

[d6u]

Just tried. t.end() doesn't count towards plan.

[Schoonology]

That's right. I meant more like this (dropping t.plan completely, as explicitly calling t.end works the same way):

const test = require('tape');
const td = require('testdouble');

test('verify invoked', function(t) {
  var stub = td.create()

  stub('any arguments', 0, 1, 2)

  td.verify(stub())

  t.end()
})

Does that work for your situation?

[d6u]

This should work. Thanks. To push this further, could testdouble.js hook up with tape and let tape count each verify() towards plan? If this is not possible now, what does it take to develop a plug in myself?

[searls]

We have a couple other plugins that hook verify into assertion libs and I suspect this should also be possible. See testdouble-chai and testdouble-jasmine for reference

[d6u]

Thanks

[searls]

Because td.verify throws an error, one option might be to use tape-catch: https://github.com/michaelrhodes/tape-catch

[customcommander]

If you really want to use t.plan(…) then I suggest you also use t.pass(…):

const test = require('tape');
const td = require('testdouble');
const SUT = require(/* … */); // Subject Under Test

test('Hello World!', t => {
  t.plan(1);
  const fn = td.func();
  SUT(fn, 42);
  td.verify(fn(42));
  t.pass('fn was applied to 42'); // <-- Counts towards t.plan
  t.end();
});

TAP Output:

# Hello World!
ok 1 fn was applied to 42