Test Class
The role of a test class is to test the public (and sometimes protected) methods of a single class.
Eclipse's JUnit integration runs each method in the test class, and then reports whether the test method passed or failed.
The test class has no main method - JUnit runs methods inside the class.
test Source Directory¶
Test classes belong in a separate source directory.
Instead of src, these classes go in test.
This separation allows an automated build tool to exclude the test directory when it packages your code for promotion.
Creating a Test Case¶
Create a new JUnit test class by selecting File->New->JUnit Test Case.
This creates the Java class, but also allows you to add JUnit code to Eclipse's Build Path.
Build Path¶
Eclipse's Build Path is where it looks for configuration, like code to include and source folders.
If you forget to add JUnit to the build path, run these steps.
- Right-click the project and select BuildPath->Configure Build Path.
- On the Libraries tab, choose Add Library.
- Select JUnit, and choose JUnit 4.
Test Class Naming¶
Name the test class to match the class it's testing, plus Tests.
public class StringManipulator {
// ...
}
public class StringManipulatorTests {
// ...
}
Package¶
The test class should share the same package as the class it tests.
* This allows access to package-only methods, and makes the class easy to find.
* The class is still in the test source directory.
Practice Exercise¶
Unit tests are especially useful when it comes time to retest our code. We must always retest when we make a change, and pressing a button to verify functionality is a lot easier than manually testing again.
Drill¶
UnitTesting/test/
UnitTesting/src/com.example.unittesting.drills.TextConverter
* Create a new JUnit test case for TextConverter. Be sure to create the correct package in the test source folder first.