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 runnerParameterized
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.The parameters can be provided as an array, too:
@Parameters public static Object[][] data() { return new Object[][] { { 0, 0 }, { 1, 1 }, { 2, 1 }, { 3, 2 }, { 4, 3 }, { 5, 5 }, { 6, 8 } }; }
Tests with single parameter
If your test needs a single parameter only, you don't have to wrap it with an array. Instead you can provide an
Iterable
or an array of objects.@Parameters public static Iterable<? extends Object> data() { return Arrays.asList("first test", "second test"); }
or
@Parameters public static Object[] data() { return new Object[] { "first test", "second test" }; }
Create different runners
By default the
Parameterized
runner creates a slightly modifiedBlockJUnit4ClassRunner
for each set of parameters. You can build an ownParameterized
runner that creates another runner for each set of parameters. Therefore you have to build aParametersRunnerFactory
that creates a runner for eachTestWithParameters
. (TestWithParameters
are bundling the parameters and the test name.) The factory must have a public zero-arg constructor.public class YourRunnerFactory implements ParameterizedRunnerFactory { public Runner createRunnerForTestWithParameters(TestWithParameters test) throws InitializationError { return YourRunner(test); } }
Use the
Parameterized.UseParametersRunnerFactory
to tell theParameterized
runner that it should use your factory.@RunWith(Parameterized.class) @UseParametersRunnerFactory(YourRunnerFactory.class) public class YourTest { ... }
- Since:
- 4.0
Nested Class Summary
Nested Classes Modifier and Type Class Description static interface
Parameterized.Parameter
Annotation for fields of the test class which will be initialized by the method annotated byParameters
.static interface
Parameterized.Parameters
Annotation for a method which provides parameters to be injected into the test class constructor byParameterized
.static interface
Parameterized.UseParametersRunnerFactory
Add this annotation to your test class if you want to generate a special runner.Nested classes/interfaces inherited from class org.junit.runners.Suite
Suite.SuiteClasses
Constructor Summary
Constructors Constructor Description Parameterized(Class<?> klass)
Only called reflectively.
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description 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, createTestClass, filter, getDescription, getName, getRunnerAnnotations, getTestClass, isIgnored, run, runLeaf, setScheduler, sort, validatePublicVoidNoArgMethods, withAfterClasses, withBeforeClasses
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 classSuite