C# | Unit Tests with xUnit and Complex Inline Data Object

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In this post, we will explore how to create unit tests using xUnit, a popular unit testing framework for .NET, with complex inline data object theory methods examples.

Introduction to xUnit

xUnit is an open-source unit testing tool for the .NET Framework. It is highly extensible and provides various features to simplify the process of writing and executing unit tests.

Setting up xUnit

Before writing unit tests, make sure you have installed the xUnit framework in your project. You can do this using NuGet Package Manager or .NET CLI.

dotnet add package xunit
dotnet add package xunit.runner.visualstudio

Writing Unit Tests with Complex Inline Data Object

Example Scenario

Let's assume we have a class Calculator with a method Add, which takes two integers as input and returns their sum. We want to test this method with different sets of input data, including complex inline data objects.

using Xunit;

public class Calculator
{
    public int Add(int a, int b)
    {
        return a + b;
    }
}

Writing Unit Tests

using Xunit;

public class CalculatorTests
{
    private readonly Calculator _calculator;

    public CalculatorTests()
    {
        _calculator = new Calculator();
    }

    [Theory]
    [InlineData(2, 3, 5)] // Simple inline data
    [InlineData(-2, -3, -5)] // Simple inline data with negative numbers
    [InlineData(0, 0, 0)] // Simple inline data with zeros
    [InlineData(1000, 500, 1500)] // Simple inline data with large numbers
    [InlineData(1, -1, 0)] // Simple inline data with mixed positive and negative numbers
    [InlineData(2147483647, 1, -2147483648)] // Simple inline data with maximum integer value
    [InlineData(-2147483648, -1, 2147483647)] // Simple inline data with minimum integer value
    [InlineData(int.MaxValue, 0, int.MaxValue)] // Simple inline data with maximum integer value and zero
    [InlineData(int.MinValue, 0, int.MinValue)] // Simple inline data with minimum integer value and zero
    [InlineData(2147483647, -2147483648, -1)] // Simple inline data with maximum and minimum integer values
    [InlineData(int.MaxValue, int.MaxValue, -2)] // Simple inline data with two maximum integer values
    [InlineData(int.MinValue, int.MinValue, 0)] // Simple inline data with two minimum integer values
    [InlineData(0, 2147483647, 2147483647)] // Simple inline data with zero and maximum integer value
    [InlineData(0, int.MinValue, int.MinValue)] // Simple inline data with zero and minimum integer value
    [InlineData(int.MinValue, int.MaxValue, -1)] // Simple inline data with maximum and minimum integer values
    public void Add_WithInlineData_ReturnsExpectedResult(int a, int b, int expected)
    {
        // Arrange

        // Act
        int result = _calculator.Add(a, b);

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

    [Theory]
    [ClassData(typeof(ComplexInlineDataGenerator))]
    public void Add_WithComplexInlineData_ReturnsExpectedResult(int a, int b, int expected)
    {
        // Arrange

        // Act
        int result = _calculator.Add(a, b);

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

public class ComplexInlineDataGenerator : IEnumerable<object[]>
{
    private readonly List<object[]> _data = new List<object[]>
    {
        new object[] { 2, 3, 5 },
        new object[] { -2, -3, -5 },
        new object[] { 0, 0, 0 },
        new object[] { 1000, 500, 1500 },
        new object[] { 1, -1, 0 },
        new object[] { 2147483647, 1, -2147483648 },
        new object[] { -2147483648, -1, 2147483647 },
        new object[] { int.MaxValue, 0, int.MaxValue },
        new object[] { int.MinValue, 0, int.MinValue },
        new object[] { 2147483647, -2147483648, -1 },
        new object[] { int.MaxValue, int.MaxValue, -2 },
        new object[] { int.MinValue, int.MinValue, 0 },
        new object[] { 0, 2147483647, 2147483647 },
        new object[] { 0, int.MinValue, int.MinValue },
        new object[] { int.MinValue, int.MaxValue, -1 }
    };

    public IEnumerator<object[]> GetEnumerator() => _data.GetEnumerator();

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

In this example:

• We have a CalculatorTests class containing tests for the Add method of the Calculator class.
• We use [Theory] attribute to denote parameterized tests.
• We use [InlineData] attribute to provide inline data for simple test cases.
• We define a custom data generator class ComplexInlineDataGenerator implementing IEnumerable<object[]> to generate complex inline data.
• The ComplexInlineDataGenerator class provides a collection of test cases with complex inline data.
• Each test case consists of three integers: a, b, and the expected result expected.
• We use Assert.Equal to verify that the actual result matches the expected result.

What Next?

By using xUnit with complex inline data object theory methods examples, we can effectively test methods with various input scenarios, ensuring the correctness and robustness of our code.