Testing

For more details checkout Testing

Unit Testing

Unit Testing Frameworks:

• NUnit
• xUnit
• MSTest

Mocking Libraries: Handle indirect outputs of SUT

• Moq
• NSubsititue
• FakeItEasy
• Microsoft Fakes

Assertion Libraries:

• Fluent Assertions

NUnit

• Setup:

  class SomethingTests
  {
      [SetUp]
      public void SetUp()
      {
  
      }
  }

• Test:

  [Test]
  public void ShouldReturnSomething()
  {
      // Arrange
  
      // Act
  
      // Assert
  }

XUnit

• Written by the developers of NUnit
• Intuitive terminology
• Excellent extensibility

Elements

• [Fact]: is always true
• [Theory]: is true with the right data
• [InlineData], [MemberData], [ClassData]: passing data to a unit test
• Constructor should be used for Set Up

Parametrized tests: Using [Theory]: represents a suite of tests that execute the same code but have different input arguments.

• [InlineData]: Pass data inline
• [MemberData]: Fetch data from a static property or method
• [ClassData]:

Example:

[Theory]
[InlineData(1, 2, 1)]
[InlineData(1, 3, 2)]
public void DiffTest(int x, int y, int expectedValue)
{
    // Arrange
    var calculator = new MathFormulas();

    // Act
    var result = calculator.Diff(x, y);

    // Assert
    Assert.Equal(expectedValue, result);
}

// Create test data
public static IEnumerable<object[]> Data =>
        new List<object[]>
        {
            new object[] { 1, 2, 3},
            new object[] { -4, -6, -10},
            new object[] { -2, 2, 0},
            new object[] { int.MinValue, -1, int.MacValue},
        };

[Theory]
[MemberData(nameof(MathFormulas.Data), MemberType = nameof(MathFormulas))]
public void AddTest(int x, int y, int expectedValue)
{
    // Arrange
    var calculator = new MathFormulas();

    // Act
    var result = calculator.Add(x, y);

    // Assert
    Assert.Equal(expectedValue, result);
}

// Create test data
public IEnumerator<object[]> GetEnumerator()
{
    yield return new object[] { 1, 2, 3};
    yield return new object[] { -4, -6, -10};
    yield return new object[] { -2, 2, 0};
    yield return new object[] { int.MinValue, -1, int.MacValue};
}

IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

[Theory]
[ClassData(nameof(MathFormulas))]
public void AddTest(int x, int y, int expectedValue)
{
    // Arrange
    var calculator = new MathFormulas();

    // Act
    var result = calculator.Add(x, y);

    // Assert
    Assert.Equal(expectedValue, result);
}

Skip Tests:

• [Fact(Skip = "the reason")]
• [Theory(Skip = "the reason")]