Three types of Test

• Unit test: testing the smallest unit of your code
• Integration test: test an entire component or subsystem
• Functional test: end-to-end functionality

Testing Java applications

To execute tests, you'll need to compile test code first. Optimally, you'll have a dedicated directory to hold the source code, and another to hold compiled test classes.

Project layout

src/test/java
src/test/resources
You can also find test results XML under build/test-results. Many test framework will transform them into reports, which can be found under build/reports/test. You need to add dependency if you want to use these frameworks, such as JUnit or TestNG.

Test configurations

There are two new configurations that can be used to declare dependencies for test code compilation or execution: testCompile and testRuntime.
An example declares a compile-time dependency JUnit.

dependencies {
  testCompile 'junit:junit:4.11'
}

Another configuration testRuntime is used for dependencies not needed for compilation but needed at runtime during execution.
Keep in mind that dependencies
assigned to test configurations don’t influence the classpath of your production code.
In other words, they’re not used for the compilation or packaging process.
However, the test configurations extend from specific configuration to handle dependencies which are needed for production code.

Test tasks

compileJava -> processResources -> classes -> jar -> compileTestJava -> processTestResources -> testClasses -> test

Tasks about test may be UP-TO-DATE to skip if there is no test source code.
And if you run 'gradle jar', the test tasks will also be skipped.

Test detection

How does Gradle figure out which classes to run?
Compiled test classes are in build/classes/test. Classes matching the following descriptions are inspected:

1. Any class or superclass that extends junit.framework.TestCase or groovy.util.GroovyTestCase
2. Any class or superclass annotated with @RunWith
3. Any class or superclass that contains one method annotated with @Test

Unit test

You can use JUnit or TestNG, or Spock.

Using JUnit

Adding the dependency

project(':repository') {
   repositories {
      mavenCentral()
   }
   dependencies {
      compile project(':model')
      testCompile 'junit:junit:4.11'
   } 
}

'testCompile' means JUnit can be used to compile the test source files.

Writing unit tests

public class InMemoryToDoRepositoryTest {
   private ToDoRepository inMemoryToDoRepository;
   @Before
   public void setUp() {
   inMemoryToDoRepository = new InMemoryToDoRepository();
  }
  @Test
  public void insertToDoItem() {
   ToDoItem newToDoItem = new ToDoItem();
   newToDoItem.setName("Write unit tests");
   Long newId = inMemoryToDoRepository.insert(newToDoItem);
   ToDoItem persistedToDoItem = inMemoryToDoRepository.findById(newId);
   assertNotNull(persistedToDoItem);
   assertEquals(newToDoItem, persistedToDoItem);
  }
 }

Executing tests

The task test will first compile the production source, and then create the JAR file followed by test sources compilation and test execution.

Using other test frameworks

Using TestNG

You need to

1. add dependency
2. Specify that TestNG should be used to execute tests by calling the method test.useTestNG().
   The build script will look like this

apply plugin: 'groovy'
dependencies {
    compile project(':model')
    testCompile group: 'org.testng', name: 'testng', version: '6.8'
}
test.useTestNG()
repositories {
    mavenCentral()
}

JUnit tests will not run anymore.

Using both JUnit and TestNG

Defining Test Tasks
We can add a new task of class type "Test" named "TestNG"

task TestNG (type: Test) {
    useTestNG()
}
test.dependsOn TestNG

In this way, every time we run gradle test will run task TestNG firstly， which enables JUnit and TestNG running simultaneously.