org.junit.runners
Class Parameterized

java.lang.Object
  org.junit.runner.Runner
      org.junit.runners.ParentRunner<Runner>
          org.junit.runners.Suite
              org.junit.runners.Parameterized

All Implemented Interfaces:

Describable, Filterable, Sortable

public class Parameterized
extends Suite

The custom runner Parameterized implements parameterized tests. When running a parameterized test class, instances are created for the cross-product of the test methods and the test data elements.

For example, to test a Fibonacci function, write:

 @RunWith(Parameterized.class)
 public class FibonacciTest {
        @Parameters(name= "{index}: fib({0})={1}")
        public static Iterable<Object[]> data() {
                return Arrays.asList(new Object[][] { { 0, 0 }, { 1, 1 }, { 2, 1 },
                 { 3, 2 }, { 4, 3 }, { 5, 5 }, { 6, 8 } });
     }

        private int fInput;

        private int fExpected;

        public FibonacciTest(int input, int expected) {
                fInput= input;
                fExpected= expected;
     }

        @Test
        public void test() {
                assertEquals(fExpected, Fibonacci.compute(fInput));
     }
 }
 

Each instance of FibonacciTest will be constructed using the two-argument constructor and the data values in the @Parameters method.

In order that you can easily identify the individual tests, you may provide a name for the @Parameters annotation. This name is allowed to contain placeholders, which are replaced at runtime. The placeholders are

{index}

the current parameter index

{0}

the first parameter value

{1}

the second parameter value

...

In the example given above, the Parameterized runner creates names like [1: fib(3)=2]. If you don't use the name parameter, then the current parameter index is used as name.

You can also write:

 @RunWith(Parameterized.class)
 public class FibonacciTest {
  @Parameters
  public static Iterable<Object[]> data() {
      return Arrays.asList(new Object[][] { { 0, 0 }, { 1, 1 }, { 2, 1 },
                 { 3, 2 }, { 4, 3 }, { 5, 5 }, { 6, 8 } });
     }
  @Parameter(0)
  public int fInput;

  @Parameter(1)
  public int fExpected;

  @Test
  public void test() {
      assertEquals(fExpected, Fibonacci.compute(fInput));
     }
 }
 

Each instance of FibonacciTest will be constructed with the default constructor and fields annotated by @Parameter will be initialized with the data values in the @Parameters method.

Since:

4.0

Nested Class Summary

static interface	Parameterized.Parameter Annotation for fields of the test class which will be initialized by the method annotated by Parameters By using directly this annotation, the test class constructor isn't needed. Index range must start at 0.
static interface	Parameterized.Parameters Annotation for a method which provides parameters to be injected into the test class constructor by Parameterized

Nested classes/interfaces inherited from class org.junit.runners.Suite

Suite.SuiteClasses

Constructor Summary

Parameterized(Class<?> klass)
Only called reflectively.

Method Summary

protected List<Runner>

getChildren() Returns a list of objects that define the children of this Runner.

Methods inherited from class org.junit.runners.Suite

describeChild, emptySuite, runChild

Methods inherited from class org.junit.runners.ParentRunner

childrenInvoker, classBlock, classRules, collectInitializationErrors, filter, getDescription, getName, getRunnerAnnotations, getTestClass, run, runLeaf, setScheduler, sort, validatePublicVoidNoArgMethods, withAfterClasses, withBeforeClasses

Methods inherited from class org.junit.runner.Runner

testCount

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Parameterized

public Parameterized(Class<?> klass)
              throws Throwable

Only called reflectively. Do not use programmatically.

Throws:

Throwable

Method Detail

getChildren

protected List<Runner> getChildren()

Description copied from class: ParentRunner

Returns a list of objects that define the children of this Runner.

Overrides:

getChildren in class Suite