freeCodeCamp/guide/english/csharp/unit-testing/index.md

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Unit Testing

Unit Testing

Unit Testing is a way of checking that a small chunk of your code, or a 'unit', works as you expect it to and it is very good practice for producing high quality code. It is particularly useful in large projects, to quickly and easily track down what unit is causing defects in your wider project. In commercial development the majority of bugs and issues with code can be mitigated through the use of unit testing. Unit testing also allows for automation testing. Unit testing is also closely used in conjunction with test driven development.

Creating a basic unit test

1. Right click Solution > Add > New Project

2. Select Unit Test App (Universal Windows) and name the UnitTest project appropriately

3. Reference the solution you are testing, by right clicking the References tab in the unit test > Add Reference and select the solution that you are referencing. Then make the class that you are testing publicly accessible.

4. Name the TestMethods appropriately, and then input the //Arrange //Act //Assert parameters within the method body code block.

5. Under the // Arrange section, each variable involved in that individual test needs to be declared, as well as the expectedResult.

6. Under the // Act section, the variables that are going to be passed as an input into a given method are placed into the method's parenthesis, and all of this is initialised as an actualResult variable.

7. Under the // Assert section, to check whether the expectedResult is equal to the actualResult and then assert this finding to make the test pass using the Assert.AreEqual(expectedResult, actualResult) class and method.

Example code

The code below is testing whether the MultiplyPointsMethod in the Multiply Points Class will output 600 from an input of 6.

[TestMethod]
		public void BonusPointsOutputTestWithInt6()
		{
			// Arrange
			var userInput = 6;
			var expectedResult = 600;

			// Act
			int actualResult = MultiplyPointsClass.MultiplyPointsMethod(userInput);

			// Assert
			Assert.AreEqual(expectedResult, actualResult);

		}

Running the test

1. Go to Test > Run > All Tests
2. If the testing window does not pop up go to Test > Windows > Test Explorer