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.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.junit.runner.Runner;
import org.junit.runner.notification.RunNotifier;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.Statement;
import org.junit.runners.model.TestClass;
/**
* <p>
* 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
* public static List<Object[]> data() {
* return Arrays.asList(new Object[][] {
* Fibonacci,
* { { 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>
*/
public class Parameterized extends Suite {
/**
* Annotation for a method which provides parameters to be injected into the
* test class constructor by <code>Parameterized</code>
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public static @interface Parameters {
}
private class TestClassRunnerForParameters extends
BlockJUnit4ClassRunner {
private final int fParameterSetNumber;
private final List<Object[]> fParameterList;
TestClassRunnerForParameters(Class<?> type,
List<Object[]> parameterList, int i) throws InitializationError {
super(type);
fParameterList= parameterList;
fParameterSetNumber= i;
}
@Override
public Object createTest() throws Exception {
return getTestClass().getOnlyConstructor().newInstance(
computeParams());
}
private Object[] computeParams() throws Exception {
try {
return fParameterList.get(fParameterSetNumber);
} catch (ClassCastException e) {
throw new Exception(String.format(
"%s.%s() must return a Collection of arrays.",
getTestClass().getName(), getParametersMethod(
getTestClass()).getName()));
}
}
@Override
protected String getName() {
return String.format("[%s]", fParameterSetNumber);
}
@Override
protected String testName(final FrameworkMethod method) {
return String.format("%s[%s]", method.getName(),
fParameterSetNumber);
}
@Override
protected void validateConstructor(List<Throwable> errors) {
validateOnlyOneConstructor(errors);
}
@Override
protected Statement classBlock(RunNotifier notifier) {
return childrenInvoker(notifier);
}
}
private final ArrayList<Runner> runners= new ArrayList<Runner>();
/**
* Only called reflectively. Do not use programmatically.
*/
public Parameterized(Class<?> klass) throws Throwable {
super(klass, Collections.<Runner>emptyList());
List<Object[]> parametersList= getParametersList(getTestClass());
for (int i= 0; i < parametersList.size(); i++)
runners.add(new TestClassRunnerForParameters(getTestClass().getJavaClass(),
parametersList, i));
}
@Override
protected List<Runner> getChildren() {
return runners;
}
@SuppressWarnings("unchecked")
private List<Object[]> getParametersList(TestClass klass)
throws Throwable {
return (List<Object[]>) getParametersMethod(klass).invokeExplosively(
null);
}
private FrameworkMethod getParametersMethod(TestClass testClass)
throws Exception {
List<FrameworkMethod> methods= testClass
.getAnnotatedMethods(Parameters.class);
for (FrameworkMethod each : methods) {
int modifiers= each.getMethod().getModifiers();
if (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))
return each;
}
throw new Exception("No public static parameters method on class "
+ testClass.getName());
}
}
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