feat: support assert.expect with reruns

[jembezmamy]

This MR adds support for assert.expect.

Currently assert.expect counts all assertions including these performed in previous tries:

  retry('should pass with retries', function (assert, currentRun) {
    assert.expect(2)
    assert.ok(true) // run twice
    if (currentRun === 1) { throw new Error('fail') }
    assert.ok(true) // run once
  })

In this example the total number of assertions is 3: 1 for the first run + 2 for the second one. The test fails even though the second attempt should be considered successful.

To mitigate this issue, I proxy the expect method and add the number of the assertions already performed in the previous runs:

  expectFn (target) {
    return count => {
      target.expect(count + target.test.assertions.length)
    }
  }

[mrloop]

Looks good. Could you add a more complex test with different with more failures on different runs? Something like:

  retry('should pass with retries', function (assert, currentRun) {
    calls.push(['with', currentRun])

    assert.expect(3)
    assert.ok(true)
    if (currentRun === 1) { throw new Error('fail') }
    assert.ok(true)
    if (currentRun === 2) { throw new Error('fail') }
    assert.ok(true)
  })

[jembezmamy]

Good point, I made the test case more complex 👍

[mrloop]

Great thanks