There are more to unit testing than using a unit testing framework - in order to succeed you want to use the right tools for the job. There are a few tools that almost no one talks about - some enabling creating of top-notch, robust unit tests. Some will help you run your tests better and faster. In this session I'll explain about the inevitable maintainability problems developers face when writing and maintaining huge unit testing suits and how unit level BDD, AutoMocking, and Continuous Execution can help take control over your tests.

1. The secret
Unit Testing tools
no one has ever told you about
Dror Helper | http://helpercode.com | @dhelper

2. Consultant & software architect
Developing software since 2002
Clean Coder & Test Driven Developer
Pluralsight author
https://www.pluralsight.com/authors/dror-helper
B: http://helpercode.com
T: @dhelper
About.ME

3. Why should you care about tools?

4. Background: unit testing tools

5. [Test]
public void AddItem_AddTwoValidProductsToCart_TotalEqualsItemsPrice()
{
var fakeRepository = A.Fake<IProductRepository>();
Product product1 = new Product(1, "product-1", 100);
Product product2 = new Product(2, "product-2", 200);
A.CallTo(() => fakeRepository.GetProductById(1)).Returns(product1));
A.CallTo(() => fakeRepository.GetProductById(2)).Returns(product2));
var shoppingCart = new ShoppingCart(fakeRepository);
shoppingCart.AddItem(1);
shoppingCart.AddItem(2);
Assert.That(shoppingCart.Total, Is.EqualTo(300));
}

6. @Test
public void addItem_addTwoValidProductsToCart_totalEqualsItemsPrice() {
IProductRepository fakeRepository = mock(IProductRepository.class);
Product product1 = new Product(1, "product-1", 100);
Product product2 = new Product(2, "product-2", 200);
when(fakeRepository.getProductById(1)).thenReturn(product1);
when(fakeRepository.getProductById(2)).thenReturn(product2);
ShoppingCart cart = new ShoppingCart(fakeRepository);
cart.AddItem(1);
cart.AddItem(2);
assertEquals(300.0, cart.getTotal(), 0);
}

7. TEST(ShoppingCartTests, AddProductById_AddTwoProducts_GetTotalPriceReturnSumPrice)
{
FakeRepository fake_repository;
Product product1 = Product(1, "product-1", 100);
Product product2 = Product(2, "product-2", 200);
EXPECT_CALL(fake_repository, GetProductById(1)).WillRepeatedly(Return(product1));
EXPECT_CALL(fake_repository, GetProductById(2)).WillRepeatedly(Return(product2));
ShoppingCart shopping_cart(fake_repository);
shopping_cart.AddProductById(1);
shopping_cart.AddProductById(2);
ASSERT_EQ(300, shopping_cart.GetTotalPrice());
}

8. (Most)
Unit Testing
Frameworks
[Test]
public void MyTest()
{
}

9. A good Unit Test should be:
Easy
to write
Simple
to read
Trivial
to maintain

10. What about AAA?
[Test]
public async void GetUserFromUrl() {
var clientFake = A.Fake<IJsonClient>();
A.CallTo(() => clientFake.HttpGetUncompressedAsync(A<string>.Ignored))
.Returns(Task.FromResult(JsonResult));
var userRepository = new UserRepository(clientFake);
var user = await userRepository.GetUser(11361);
var expected = new User {
Id=11361, DisplayName = "Dror Helper", ImageUrl=DefaultAvatar, Reputation=13904
};
Assert.That(user, Is.EqualTo(expected));
}
Arrange
 Act
 Assert

11. Test setup (Arrange)

12. Arrange issues
[TestMethod]
public async Task LoadUser_ReputationStaysTheSame_ReputationTrendSame() {
var user1 = new User {ImageUrl = "http://dummy.jpg", Reputation = 10};
var user2 = new User {ImageUrl = "http://dummy.jpg", Reputation = 10};
var fakeUserRepository = new FakeUserRepository(new[] { user1, user2 });
var viewModel = await InvokeAsync(() => new UserDetailsViewModel(fakeUserRepository));
await viewModel.LoadUser();
await viewModel.LoadUser();
var result = await InvokeAsync(() => ((SolidColorBrush)viewModel.ReputationTrend).Color);
Assert.AreEqual(Colors.White, result);
}

13. [TestInitialize]
public async Task InitializeViewModel() {
var user1 = new User {ImageUrl = "http://dummy.jpg", Reputation = 10};
var user2 = new User {ImageUrl = "http://dummy.jpg", Reputation = 10};
var fakeUserRepository = new FakeUserRepository(new[] { user1, user2 });
_viewModel = await InvokeAsync(() => new UserDetailsViewModel(fakeUserRepository));
}
[TestMethod]
public async Task LoadUser_ReputationStaysTheSame_ReputationTrendSame() {
await _viewModel.LoadUser();
await _viewModel.LoadUser();
var result = await InvokeAsync(() => ((SolidColorBrush)_viewModel.ReputationTrend).Color);
Assert.AreEqual(Colors.White, result);
}
Using Setup/TearDown

14. [TestInitialize]
public async Task InitializeViewModel() {
var user1 = new User {ImageUrl = "http://dummy.jpg", Reputation = 10};
var user2 = new User {ImageUrl = "http://dummy.jpg", Reputation = 10};
var fakeUserRepository = new FakeUserRepository(new[] { user1, user2 });
_viewModel = await InvokeAsync(() => new UserDetailsViewModel(fakeUserRepository));
}
[TestMethod]
public async Task LoadUser_ReputationStaysTheSame_ReputationTrendSame() {
await _viewModel.LoadUser();
await _viewModel.LoadUser();
var result = await InvokeAsync(() => ((SolidColorBrush)_viewModel.ReputationTrend).Color);
Assert.AreEqual(Colors.White, result);
}
private UserDetailsViewModel _viewModel;

15. Abusing Setup
methods

16. Extract to methods
[TestMethod]
public async Task LoadUser_ReputationStaysTheSame_ReputationTrendSame() {
var user1 = CreateUser(10);
var user2 = CreateUser(10);
var fakeUserRepository = new FakeUserRepository(new[] { user1, user2 });
var viewModel = await InvokeAsync(() => new UserDetailsViewModel(fakeUserRepository));
await viewModel.LoadUser();
await viewModel.LoadUser();
var result = await InvokeAsync(() => ((SolidColorBrush)viewModel.ReputationTrend).Color);
Assert.AreEqual(Colors.White, result);
}

17. Over abstraction
[TestMethod]
public async Task LoadUser_ReputationStaysTheSame_ReputationTrendSame() {
var fakeUserRepository = new FakeUserRepository(new[] { user1, user2 });
var viewModel = InitializeSystem(10, 10);
await RunTest(2);
CheckColor(Colors.White)
}

18. The problem with Factories
private User CreateUser(int reputation) {
return new User
{
ImageUrl = "http://dummy.jpg",
Reputation = reputation
};
}
private User CreateUser(int reputation, string imageUrl) {
return new User
{
ImageUrl = imageUrl,
Reputation = reputation
};
}

19. Solution: Builder Pattern
class UserBuilder {
private int _id, _reputation;
private string _name, _imageUrl;
public UserBuilder() {
_id = 1;
_name = "dummy";
_imageUrl = "http://dummy.jpg";
}
User Build() {
return new User {
Id = _id, Name = _name, ImageUrl = _imageUrl, Reputation = _reputation
};
}
}

20. Builder Pattern (cont)
class UserBuilder {
...
public UserBuilder WithName(string name) {
_name = name
return this;
}
public UserBuilder WithReputation(int reputation) {
_reputation = reputation
return this;
}
...
}
var user1 = new UserBuilder()
.WithReputation(10)
.Build();

21. Tool: AutoMocking Containers
Test Container SUT
http://blog.ploeh.dk/2013/03/11/auto-mocking-containe
New()
Configure
CreateCreate SUT
Act

22. Verification (Assert)

23. Can you spot the problem?
[TestMethod]
public void PerformSomeActionReturns42()
{
var myClass = ...
bool initOk = myClass.Initialize();
var result = myClass.PerformSomeAction();
Assert.IsTrue(initOk);
Assert.AreEqual(42, result);
}

24. How about now?
[TestMethod]
public void TestPasswordComplexity()
{
var result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "1!").Result;
Assert.IsFalse(result.Succeeded);
result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "123456789").Result;
Assert.IsFalse(result.Succeeded);
result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "123456789!").Result;
Assert.IsFalse(result.Succeeded);
result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "abcdefghijk").Result;
Assert.IsFalse(result.Succeeded);
result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "abcdefghijK1!").Result;
Assert.IsTrue(result.Succeeded);
}
http://stackoverflow.com/q/26400537/11361

25. How many Asserts per test?
One Assert per test
2 Asserts == 2 Tests
Really???

26. Multiple Asserts can make sense
[TestMethod]
public void CompareTwoAsserts()
{
var actual = GetNextMessage();
Assert.AreEqual(1, actual.Id);
Assert.AreEqual("str-1", actual.Content);
}

27. HOW UNIT TESTING FRAMEWORKS HURT YOUR UNIT TESTING EFFORTS
WHY TESTS THROW EXCEPTIONS ON FAILURE?
It’s trivial, and best practice
Helps Decouple test runner from test
But not necessary…

28. public class AssertAll
{
public static void Execute(params Action[] assertionsToRun)
{
var errorMessages = new List<exception>();
foreach (var action in assertionsToRun)
{
try
{
action.Invoke();
}
catch (Exception exc)
{
errorMessages.Add(exc);
}
}
if(errorMessages.Any())
{
string errorMessage = string.Join("n", errorMessages);
Assert.Fail($"The following conditions failed:n{errorMessage}"));
}
}
}
http://blog.drorhelper.com/2011/02/multiple-asserts-done-right.html

29. Using Assert.All
[TestMethod]
public void CompareTwoAsserts()
{
var actual = CreateMessage();
AssertAll.Execute(
() => Assert.AreEqual(1, actual.Id),
() => Assert.AreEqual("str-1", actual.Content);
}

30. Some frameworks are catching up!
https://github.com/nunit/docs/wiki/Multiple-Asserts

31. @Test
void dependentAssertions() {
assertAll("properties",
() -> {
String firstName = person.getFirstName();
assertNotNull(firstName);
// Executed only if the previous assertion is valid.
assertAll("first name",
() -> assertTrue(firstName.startsWith("J")),
() -> assertTrue(firstName.endsWith("n")));
},
() -> {
String lastName = person.getLastName();
assertNotNull(lastName);
// Executed only if the previous assertion is valid.
assertAll("last name",
() -> assertTrue(lastName.startsWith("D")),
() -> assertTrue(lastName.endsWith("e")));
});
}

32. Assert.AreEqual(5, 2 + 2); Assert.AreEqual(2 + 2, 5)

33. Assert.AreEqual(5, 2 + 2); Assert.IsTrue(2 + 2 == 5)

34. How to choose the right Assert?
• IsTrue vs. AreEqual
• Parameter ordering confusion
• StringAssert/CollectionAssert
It’s all about proper error messages

35. AssertHelper
[Test]
public void CompareTest()
{
var myClass = new MyClass();
Expect.That(() => myClass.ReturnFive() == 10);
}
[Test]
public void CompareTest()
{
var c1 = new[] { 1, 2, 3, 4, 5 }
Expect.That(() => c1.Contains(42);
}
https://github.com/dhelper/AssertHelper

36. Assertion Libraries: FluentAssertions
[Fact]
public void CompareTwoObjects()
{
var customer1 = new Customer("cust-1", "John Doe");
var customer2 = new Customer("cust-2", "John Doe");
customer1.ShouldBeEquivalentTo(customer2,
o => o.Excluding(customer => customer.Id));
}
http://www.fluentassertions.com/

37. Test organization

38. Test structure issues
• What to call the test?
• AAA is not mandatory
• What should I test?
• How to avoid unreadable, complicated tests?
- Unit testing framework provide no structure

39. The BDD approach
Step
Definitions

40. Specifications == focused test
Feature: Addition
In order to avoid silly mistakes
As a math idiot
I want to be told the sum of two numbers
Scenario: Add two numbers
Given I have entered 50 into the calculator
And I have entered 70 into the calculator
When I press add
Then the result should be 120 on the screen

41. BDD Example: SpecFlow
http://www.specflow.org/

42. [TestClass]
public class CardHasBeenDisabled {
private Card _card;
private Atm _subject;
void GivenTheCardIsDisabled() {
_card = new Card(false, 100);
_subject = new Atm(100);
}
void WhenTheAccountHolderRequestsMoney() {
_subject.RequestMoney(_card, 20);
}
void ThenTheAtmShouldRetainTheCard() {
Assert.IsTrue(_subject.CardIsRetained);
}
void AndTheAtmShouldSayTheCardHasBeenRetained() {
Assert.AreEqual(DisplayMessage.CardIsRetained, _subject.Message);
}
[TestMethod]
public void Execute()
{
this.BDDfy();
}
}
Tool: BDDfy

43. Test execution

44. Continuous Testing Tools
DotCover
Typemock
Runner
nCrunch
VS2017
(Enterprise)

45. The right tools will help you write good tests
Arrange
Builder
Pattern
AutoMocking
Containers
Assert
Multiple
Asserts
3rd party
Assertion
libraries
Test
Structure
“Classic” BDD
In-Code BDD
Continuous
Testing
Typemock Runner
DotCover
nCrunch
Live Unit Testing
Infinitest (Java)
Corvlet (.NET Core)

46. Thank you
@dhelper | http://helpercode.com