Handle synchronous TestFailure within async fn body

[aaronlademann-wf]

Motivation

@josephnaberhaus-wk pointed out that when the async modifier is added to the waitFor callback, any expect() within the callback that fails will cause waitFor to throw immediately instead of continuing to call the callback on an interval.

Essentially - the issue is that currently, the first test will fail immediately instead of waiting for numRuns to get to 5, whereas the second test will pass since it's not async.

test('this will fail as a result of the async modifier on the callback', () async {
  var numRuns = 0;
  await rtl.waitFor(() async {
    numRuns++;
    expect(numRuns, 5);
  });
});

test('this will pass', () async {
  var numRuns = 0;
  await rtl.waitFor(() {
    numRuns++;
    expect(numRuns, 5);
  });
});

@greglittlefield-wf @joebingham-wk @sydneyjodon-wk I am unsure if handling synchronous failures like this is desired behavior, but I am putting up this PR since I was able to get something working that seems to also preserve the existing behaviors of waiting for things like one of RTL's async matchers (findBy*).

Changes

Only call onDone() when the error thrown from the async function is not a TestFailure. If it is a TestFailure, store that failure as the lastError like we do when an error is thrown from a synchronous callback, and keep trying the callback until a timeout occurs.

These changes make it so that both of the test cases shown above will pass as expected.

Release Notes

Add support for synchronous test failures within an asynchronous callback in the waitFor utility.

[aviary-wf]

Security Insights

No security relevant content was detected by automated scans.

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

---

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[greglittlefield-wf]

+10

semver +1

[aaronlademann-wf]

@Workiva/release-management-pp

[rmconsole-wf]

+1 from RM