Effective Unit Testing

Transcript

1. Effective Unit Testing Effective Unit Testing Courtesy of Rob Maher and Jay Fields
2. Rob Maher?
3. Jay Fields?
4. WEWUT!
5. WEWUT?
7. Do yourself a favour Buy it Read it
8. Effective Unit Testing? Effective Unit Testing? The circle of unit testing pain
9. Who unit tests? Who unit tests?
10. Effective Unit Testing? Effective Unit Testing? “ I need to write tests? “ This is hard to test! “ These tests are fragile! “ These tests are slow/suck
11. Test Rage
13. Test Smells Test Smells Slow tests Tests which don't test what they claim to Fragile tests Tests which make refactoring hard
14. Slow tests are Slow tests are useless tests useless tests In February we had: 1686 "unit" tests ran in 5:11s 5.4 tests/sec estimated if nothing changed - our test suite would be taking > 20 minutes by the end of this year.
15. Slow tests are Slow tests are useless tests useless tests In February we had: 1686 "unit" tests in 5:11s 5.4 tests/sec estimated if nothing changed - our test suite would be taking > 20 minutes by the end of this year. In the BEST CASE
16. Slow tests are Slow tests are useless tests useless tests
17. Slow tests are Slow tests are useless tests useless tests
20. Getting slower!
21. Groom the tests!
23. Before 1909 Tests 97.1 Seconds
24. After 1902 Tests 25.6 Seconds
25. 3.8 X Faster!!!!!! 3.8 X Faster!!!!!!
26. Tests which don't test what Tests which don't test what they claim to they claim to
27. “ Would you understand what this test was testing if it didn't have a name?
28. [Test] public void Can_Retrive_Active_MediaSources() { MediaSource[] m = MediaSource.FindAll(MediaSource.Active); Assert.Greater(m.Length, 0); }
29. WTH DOES THIS EVEN TEST? [Test] public void Can_Retrive_Active_MediaSources() { MediaSource[] m = MediaSource.FindAll(MediaSource.Active); Assert.Greater(m.Length, 0); }
30. How do I get better How do I get better at writing tests? at writing tests?
31. Fragile tests Tests which make refactoring hard
32. TRY WRITING YOUR TRY WRITING YOUR TEST FIRST! TEST FIRST! At least some of the time
33. Katas Katas Code Retreat Code Retreat Training (Roy Training (Roy Osherove) Osherove)
34. Find someone to Find someone to read your tests read your tests Thanks @robfe @bittercoder @hammett and the Castle Project for reading my tests
35. Pair with someone Pair with someone
36. Read good tests (tm) Read good tests (tm)
37. “ The only way to get The only way to get better is to get better is to get constructive constructive feedback on your feedback on your tests tests
38. Write bad tests Write bad tests
39. [Test] public void when_candidates_are_newer_and_older_then_count_should_be_correct() { JobApp.DeleteAll(); Candidate.DeleteAll(); Candidate candidate; var aWeekAgo = DateTime.Now.AddDays(-7); for (int i = 0; i < 5; i++) { candidate = ObjectMother.NewCandidate(); candidate.User.LastLogin = aWeekAgo; //login a week ago candidate.Save(); } candidate = ObjectMother.NewCandidate(); candidate.Save(); var yesterday = DateTime.Now.AddDays(-1); DataPurgeSummary query = new DataPurgeSummary() .WithLoginBefore(yesterday); var results = query.BuildCriteria(); results[0].Candidates.ShouldBe(5); results[0].LastLogin.Value.Date.ShouldBe(aWeekAgo.Date); }
40. Lots of bad tests Lots of bad tests
41. [Test] public void Can_Retrive_Active_MediaSources() { MediaSource[] m = MediaSource.FindAll(MediaSource.Active); Assert.Greater(m.Length, 0); }
42. Seriously Seriously
43. [Test] public void TestCandidateSavesandLoads() { Candidate c = ObjectMother.NewCandidate(); string email = c.User.Email; Candidate c2 = Candidate.Find(c.Id); User u2 = c.User; Assert.IsNotNull(u2); Assert.IsNotNull(c2); Assert.AreEqual(u2.FullName, c.FirstName + ' ' + c.LastName); Assert.AreEqual(u2.Passwd, "pass"); Assert.AreEqual(u2.Email, email); Assert.AreEqual(u2.UserType, UserTypes.Candidate); Assert.AreEqual(c2.FirstName, "first"); Assert.AreEqual(c2.LastName, "last"); Assert.AreEqual(c2.Title, "mr"); Assert.AreEqual(c2.Address1, "address1"); Assert.AreEqual(c2.Address2, "address2"); Assert.AreEqual(c2.Address3, "address3"); Assert.AreEqual(c2.Town, "town"); Assert.AreEqual(c2.PostCode, "postcode"); Assert.AreEqual(c2.Country, "country"); Assert.AreEqual(c2.DaytimePhone, "dayphone"); Assert.AreEqual(c2.EveningPhone, "eveningphone"); Assert.AreEqual(c2.Mobile, "mobile"); Assert.AreEqual(c2.CandidateType, Candidate.Types.Previous); }
44. Experiment Experiment
45. Delete Bad tests Delete Bad tests But replace them with better ones!
46. Tools Tools https://github.com/PowerAssert/PowerAssert.Net https://github.com/robfe/SpecLight http://approvaltests.sourceforge.net/
47. Warning! Warning! You will write bad You will write bad tests using these tests using these tools! tools!
48. But (hopefully) you But (hopefully) you will learn some will learn some things things
49. [Test] public void TestCandidateSavesandLoads() { Candidate c = ObjectMother.NewCandidate(); string email = c.User.Email; Candidate c2 = Candidate.Find(c.Id); User u2 = c.User; Assert.IsNotNull(u2); Assert.IsNotNull(c2); Assert.AreEqual(u2.FullName, c.FirstName + ' ' + c.LastName); Assert.AreEqual(u2.Passwd, "pass"); Assert.AreEqual(u2.Email, email); Assert.AreEqual(u2.UserType, UserTypes.Candidate); Assert.AreEqual(c2.FirstName, "first"); Assert.AreEqual(c2.LastName, "last"); Assert.AreEqual(c2.Title, "mr"); Assert.AreEqual(c2.Address1, "address1"); Assert.AreEqual(c2.Address2, "address2"); Assert.AreEqual(c2.Address3, "address3"); Assert.AreEqual(c2.Town, "town"); Assert.AreEqual(c2.PostCode, "postcode"); Assert.AreEqual(c2.Country, "country"); Assert.AreEqual(c2.DaytimePhone, "dayphone"); Assert.AreEqual(c2.EveningPhone, "eveningphone"); Assert.AreEqual(c2.Mobile, "mobile"); Assert.AreEqual(c2.CandidateType, Candidate.Types.Previous); }
50. SpecLight SpecLight [Test] public void name_is_irrelevant() { new Spec("Properties of a candidate should persist and hydrate correctly") .Given(TheCandidateService) .And(ASavedValidCandidate) .When(IFetchTheCandidate) .Then(TheFetchedCandidateShouldBeProperlyInitalized) .Execute(); }
51. SpecLight SpecLight // Given void TheCandidateService() { _candidateService = new CandidateService(); } void ASavedValidCandidate() { _savedCandidate = _candidateService.Save(new Candidate()); } // When void IFetchTheCandidate() { _fetchedCandidate = _candidateService.Fetch(_savedCandidate.Id); } // Then void TheFetchedCandidateShouldBeProperlyInitalized() { PAssert.IsTrue(()=> _fetchedCandidate.FullName == "Some sample" && _fetchedCandidate.Create }
52. Power Assert Power Assert [Test] public void SequenceEqualButNotOperatorEquals() { object list = new List<int> { 1, 2, 3 }; object array = new[] { 1, 2, 3 }; PAssert.IsTrue(() => list == array); } System.Exception : IsTrue failed, expression was: list == array . . __ . . \ _/ | \_ _/ | | [1, 2, 3] | False, but would have been True with .SequenceEqual() [1, 2, 3]
53. Approval Tests Approval Tests 1. Originally a legacy testing framework 2. We use for state based testing of complex structures
54. Approval Tests Approval Tests [Test] public void Authenticate_When_Failure_Should_ReturnInvalidAuthTokenResponse() { var badResult = (JsonResult)ControllerToTest.Authenticate(new Guid("EA917962-6E1B-4064-828E var badApiResponse = (ApiResponse)badResult.Data; var badAuthResponse = (AuthenticateResponse)badApiResponse.Data; Assert.IsNotNull(badResult); Assert.IsNotNull(badApiResponse); Assert.IsNotNull(badAuthResponse); Assert.IsNull(badAuthResponse.SessionToken); Assert.AreEqual(ApiResponseCode.InvalidAuthToken, badApiResponse.Status.Code); }
55. [Test] public void Authenticate_When_Failure_Should_ReturnInvalidAuthTokenResponse() { var result = ControllerToTest.Authenticate(new Guid("EA917962-6E1B-4064-828E-941B9C40687D") Approvals.Verify(result); } Approval Tests Approval Tests { "Status": { "Code": 7, "Message": "An unexpected error occurred." }, "Data": null }
56. Approval Tests Approval Tests Downsides: 1. Terrible CI failure messages 2. Over specified tests 3. Separates test from "state assertion" (single line approvals)
57. Not a framework problem! Not a framework problem!
58. Not a framework problem! Not a framework problem! [Test] public void ExpiredGuestPayment_Should_NotBeFetched() { var paymentQueryService = new Mock<IPaymentsQueryService>(); var payment = PaymentFor(PaymentSource.Kiosk); payment.SetStatusForTesting(PaymentStatus.Error); payment.SetExpired(); paymentQueryService.Setup(q => q.GetPaymentByToken(Guid.Empty)).Returns(payment); var blackboard = Blackboard(); var action = new FetchExistingNewOrRetryableCardPaymentAction(paymentQueryService.Object); //+Act var outcome = action.Execute(blackboard); //+Assert PAssert.IsTrue(() => blackboard.Payment == null && outcome == PaymentActionOutcome.Halt); }
59. Not a framework problem! Not a framework problem! [SetUp] public void Setup() { var webhooksService = new Mock<IWebhooksService>(); calls = webhooksService.StoreInvocations<IWebhooksService, string, WebhookEvent>(d => d.Sen action = new SendPaymentCreatedWebhookAction(webhooksService.Object); blackboard = new PaymentBlackboard(null) { Payment = new Payment(CardPaymentGateway.PushpayTest, null) { Token = new Guid("5469FCCA-AE63-43E5-B548-9834436485EC"), Recipient = new Merchant { Id=456, Handle = "spca"} } }; } [Test] public void When_NotAch_Should_Send_Webhook_Event() { var result = action.Execute(blackboard); PAssert.IsTrue(() => result == PaymentActionOutcome.Continue && calls.Count == 1); } [Test] public void When_Ach_should_Not_Send_Webhook_Event() { blackboard.Method = new AchBankAccount(); var result = action.Execute(blackboard); PAssert.IsTrue(() => result == PaymentActionOutcome.Continue && calls.Count == 0); }
60. Things Things Wewut! Gary Bernhardt Sandi Metz - Magic Tricks of Testing