Tests Arange-Act-Assert Pattern

link: Unit Testing

Arange-Act-Assert Pattern

Overview

The Arrange-Act-Assert (AAA) pattern is a structured approach to writing unit tests. It divides the test into three distinct sections:

• Arrange: Set up the test environment, including any necessary objects, data, or configurations.
• Act: Perform the action that you want to test.
• Assert: Verify that the action produced the expected results.

This pattern promotes clarity and maintainability by clearly separating the different phases of the test, making it easier to understand and manage.

C# Examples of Unit Tests with AAA Pattern

Testing a Calculator Add Method

using NUnit.Framework;
 
namespace CalculatorTests
{
    public class Calculator
    {
        public int Add(int a, int b) => a + b;
    }
 
    [TestFixture]
    public class CalculatorTests
    {
        [Test]
        public void Add_ShouldReturnSumOfTwoNumbers()
        {
            // Arrange
            var calculator = new Calculator();
            int number1 = 5;
            int number2 = 10;
 
            // Act
            int result = calculator.Add(number1, number2);
 
            // Assert
            Assert.AreEqual(15, result);
        }
    }
}