package org.junit.runners;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.junit.runner.Runner;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.TestClass;
import org.junit.runners.parameterized.BlockJUnit4ClassRunnerWithParametersFactory;
import org.junit.runners.parameterized.ParametersRunnerFactory;
import org.junit.runners.parameterized.TestWithParameters;
/**
* The custom runner <code>Parameterized</code> 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.
* <p>
* For example, to test a Fibonacci function, write:
* <pre>
* @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));
* }
* }
* </pre>
* <p>
* Each instance of <code>FibonacciTest</code> will be constructed using the
* two-argument constructor and the data values in the
* <code>@Parameters</code> method.
* <p>
* In order that you can easily identify the individual tests, you may provide a
* name for the <code>@Parameters</code> annotation. This name is allowed
* to contain placeholders, which are replaced at runtime. The placeholders are
* <dl>
* <dt>{index}</dt>
* <dd>the current parameter index</dd>
* <dt>{0}</dt>
* <dd>the first parameter value</dd>
* <dt>{1}</dt>
* <dd>the second parameter value</dd>
* <dt>...</dt>
* <dd>...</dd>
* </dl>
* <p>
* In the example given above, the <code>Parameterized</code> runner creates
* names like <code>[1: fib(3)=2]</code>. If you don't use the name parameter,
* then the current parameter index is used as name.
* <p>
* You can also write:
* <pre>
* @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));
* }
* }
* </pre>
* <p>
* Each instance of <code>FibonacciTest</code> will be constructed with the default constructor
* and fields annotated by <code>@Parameter</code> will be initialized
* with the data values in the <code>@Parameters</code> method.
*
* <p>
* The parameters can be provided as an array, too:
*
* <pre>
* @Parameters
* public static Object[][] data() {
* return new Object[][] { { 0, 0 }, { 1, 1 }, { 2, 1 }, { 3, 2 }, { 4, 3 },
* { 5, 5 }, { 6, 8 } };
* }
* </pre>
*
* <h3>Tests with single parameter</h3>
* <p>
* If your test needs a single parameter only, you don't have to wrap it with an
* array. Instead you can provide an <code>Iterable</code> or an array of
* objects.
* <pre>
* @Parameters
* public static Iterable<? extends Object> data() {
* return Arrays.asList("first test", "second test");
* }
* </pre>
* <p>
* or
* <pre>
* @Parameters
* public static Object[] data() {
* return new Object[] { "first test", "second test" };
* }
* </pre>
*
* <h3>Create different runners</h3>
* <p>
* By default the {@code Parameterized} runner creates a slightly modified
* {@link BlockJUnit4ClassRunner} for each set of parameters. You can locate an
* own {@code Parameterized} runner that creates another runner for each set of
* parameters. Therefore you have to locate a {@link ParametersRunnerFactory}
* that creates a runner for each {@link TestWithParameters}. (
* {@code TestWithParameters} are bundling the parameters and the test name.)
* The factory must have a public zero-arg constructor.
*
* <pre>
* public class YourRunnerFactory implements ParameterizedRunnerFactory {
* public Runner createRunnerForTestWithParameters(TestWithParameters test)
* throws InitializationError {
* return YourRunner(test);
* }
* }
* </pre>
* <p>
* Use the {@link UseParametersRunnerFactory} to tell the {@code Parameterized}
* runner that it should use your factory.
*
* <pre>
* @RunWith(Parameterized.class)
* @UseParametersRunnerFactory(YourRunnerFactory.class)
* public class YourTest {
* ...
* }
* </pre>
*
* @since 4.0
*/
public class Parameterized extends Suite {
/**
* Annotation for a method which provides parameters to be injected into the
* test class constructor by <code>Parameterized</code>. The method has to
* be public and static.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public static @interface Parameters {
/**
* Optional pattern to derive the test's name from the parameters. Use
* numbers in braces to refer to the parameters or the additional data
* as follows:
* <pre>
* {index} - the current parameter index
* {0} - the first parameter value
* {1} - the second parameter value
* etc...
* </pre>
* <p>
* Default value is "{index}" for compatibility with previous JUnit
* versions.
*
* @return {@link MessageFormat} pattern string, except the index
* placeholder.
* @see MessageFormat
*/
String name() default "{index}";
}
/**
* Annotation for fields of the test class which will be initialized by the
* method annotated by <code>Parameters</code>.
* By using directly this annotation, the test class constructor isn't needed.
* Index range must start at 0.
* Default value is 0.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public static @interface Parameter {
/**
* Method that returns the index of the parameter in the array
* returned by the method annotated by <code>Parameters</code>.
* Index range must start at 0.
* Default value is 0.
*
* @return the index of the parameter.
*/
int value() default 0;
}
/**
* Add this annotation to your test class if you want to generate a special
* runner. You have to specify a {@link ParametersRunnerFactory} class that
* creates such runners. The factory must have a public zero-arg
* constructor.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface UseParametersRunnerFactory {
/**
* @return a {@link ParametersRunnerFactory} class (must have a default
* constructor)
*/
Class<? extends ParametersRunnerFactory> value() default BlockJUnit4ClassRunnerWithParametersFactory.class;
}
private static final ParametersRunnerFactory DEFAULT_FACTORY = new BlockJUnit4ClassRunnerWithParametersFactory();
private static final List<Runner> NO_RUNNERS = Collections.<Runner>emptyList();
private final List<Runner> fRunners;
/**
* Only called reflectively. Do not use programmatically.
*/
public Parameterized(Class<?> klass) throws Throwable {
super(klass, NO_RUNNERS);
ParametersRunnerFactory runnerFactory = getParametersRunnerFactory(
klass);
Parameters parameters = getParametersMethod().getAnnotation(
Parameters.class);
fRunners = Collections.unmodifiableList(createRunnersForParameters(
allParameters(), parameters.name(), runnerFactory));
}
private ParametersRunnerFactory getParametersRunnerFactory(Class<?> klass)
throws InstantiationException, IllegalAccessException {
UseParametersRunnerFactory annotation = klass
.getAnnotation(UseParametersRunnerFactory.class);
if (annotation == null) {
return DEFAULT_FACTORY;
} else {
Class<? extends ParametersRunnerFactory> factoryClass = annotation
.value();
return factoryClass.newInstance();
}
}
@Override
protected List<Runner> getChildren() {
return fRunners;
}
private TestWithParameters createTestWithNotNormalizedParameters(
String pattern, int index, Object parametersOrSingleParameter) {
Object[] parameters= (parametersOrSingleParameter instanceof Object[]) ? (Object[]) parametersOrSingleParameter
: new Object[] { parametersOrSingleParameter };
return createTestWithParameters(getTestClass(), pattern, index,
parameters);
}
@SuppressWarnings("unchecked")
private Iterable<Object> allParameters() throws Throwable {
Object parameters = getParametersMethod().invokeExplosively(null);
if (parameters instanceof Iterable) {
return (Iterable<Object>) parameters;
} else if (parameters instanceof Object[]) {
return Arrays.asList((Object[]) parameters);
} else {
throw parametersMethodReturnedWrongType();
}
}
private FrameworkMethod getParametersMethod() throws Exception {
List<FrameworkMethod> methods = getTestClass().getAnnotatedMethods(
Parameters.class);
for (FrameworkMethod each : methods) {
if (each.isStatic() && each.isPublic()) {
return each;
}
}
throw new Exception("No public static parameters method on class "
+ getTestClass().getName());
}
private List<Runner> createRunnersForParameters(
Iterable<Object> allParameters, String namePattern,
ParametersRunnerFactory runnerFactory)
throws InitializationError,
Exception {
try {
List<TestWithParameters> tests = createTestsForParameters(
allParameters, namePattern);
List<Runner> runners = new ArrayList<Runner>();
for (TestWithParameters test : tests) {
runners.add(runnerFactory
.createRunnerForTestWithParameters(test));
}
return runners;
} catch (ClassCastException e) {
throw parametersMethodReturnedWrongType();
}
}
private List<TestWithParameters> createTestsForParameters(
Iterable<Object> allParameters, String namePattern)
throws Exception {
int i = 0;
List<TestWithParameters> children = new ArrayList<TestWithParameters>();
for (Object parametersOfSingleTest : allParameters) {
children.add(createTestWithNotNormalizedParameters(namePattern,
i++, parametersOfSingleTest));
}
return children;
}
private Exception parametersMethodReturnedWrongType() throws Exception {
String className = getTestClass().getName();
String methodName = getParametersMethod().getName();
String message = MessageFormat.format(
"{0}.{1}() must return an Iterable of arrays.",
className, methodName);
return new Exception(message);
}
private static TestWithParameters createTestWithParameters(
TestClass testClass, String pattern, int index, Object[] parameters) {
String finalPattern = pattern.replaceAll("\\{index\\}",
Integer.toString(index));
String name = MessageFormat.format(finalPattern, parameters);
return new TestWithParameters("[" + name + "]", testClass,
Arrays.asList(parameters));
}
}