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copied!<p>Ok, here is a quick mock-up of how JUnit 4 runs parameterized tests, but done in JUnit 3.8.2.</p> <p>Basically I'm subclassing and badly hijacking the TestSuite class to populate the list of tests according to the cross-product of testMethods and parameters. </p> <p>Unfortunately I've had to copy a couple of helper methods from TestSuite itself, and a few details are not perfect, such as the names of the tests in the IDE being the same across parameter sets (JUnit 4.x appends <code>[0]</code>, <code>[1]</code>, ...).</p> <p>Nevertheless, this seems to run fine in the text and AWT <code>TestRunner</code>s that ship with JUnit as well as in Eclipse.</p> <p>Here is the ParameterizedTestSuite, and further down a (silly) example of a parameterized test using it.</p> <p>(final note : I've written this with Java 5 in mind, it <em>should</em> be trivial to adapt to 1.4 if needed)</p> <p><em>ParameterizedTestSuite.java:</em></p> <pre><code>package junit.parameterized; import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.util.ArrayList; import java.util.Collection; import junit.framework.Test; import junit.framework.TestCase; import junit.framework.TestSuite; public class ParameterizedTestSuite extends TestSuite { public ParameterizedTestSuite( final Class<? extends TestCase> testCaseClass, final Collection<Object[]> parameters) { setName(testCaseClass.getName()); final Constructor<?>[] constructors = testCaseClass.getConstructors(); if (constructors.length != 1) { addTest(warning(testCaseClass.getName() + " must have a single public constructor.")); return; } final Collection<String> names = getTestMethods(testCaseClass); final Constructor<?> constructor = constructors[0]; final Collection<TestCase> testCaseInstances = new ArrayList<TestCase>(); try { for (final Object[] objects : parameters) { for (final String name : names) { TestCase testCase = (TestCase) constructor.newInstance(objects); testCase.setName(name); testCaseInstances.add(testCase); } } } catch (IllegalArgumentException e) { addConstructionException(e); return; } catch (InstantiationException e) { addConstructionException(e); return; } catch (IllegalAccessException e) { addConstructionException(e); return; } catch (InvocationTargetException e) { addConstructionException(e); return; } for (final TestCase testCase : testCaseInstances) { addTest(testCase); } } private Collection<String> getTestMethods( final Class<? extends TestCase> testCaseClass) { Class<?> superClass= testCaseClass; final Collection<String> names= new ArrayList<String>(); while (Test.class.isAssignableFrom(superClass)) { Method[] methods= superClass.getDeclaredMethods(); for (int i= 0; i < methods.length; i++) { addTestMethod(methods[i], names, testCaseClass); } superClass = superClass.getSuperclass(); } return names; } private void addTestMethod(Method m, Collection<String> names, Class<?> theClass) { String name= m.getName(); if (names.contains(name)) return; if (! isPublicTestMethod(m)) { if (isTestMethod(m)) addTest(warning("Test method isn't public: "+m.getName())); return; } names.add(name); } private boolean isPublicTestMethod(Method m) { return isTestMethod(m) && Modifier.isPublic(m.getModifiers()); } private boolean isTestMethod(Method m) { String name= m.getName(); Class<?>[] parameters= m.getParameterTypes(); Class<?> returnType= m.getReturnType(); return parameters.length == 0 && name.startsWith("test") && returnType.equals(Void.TYPE); } private void addConstructionException(Exception e) { addTest(warning("Instantiation of a testCase failed " + e.getClass().getName() + " " + e.getMessage())); } } </code></pre> <p><em>ParameterizedTest.java:</em></p> <pre><code>package junit.parameterized; import java.util.Arrays; import java.util.Collection; import junit.framework.Test; import junit.framework.TestCase; import junit.parameterized.ParameterizedTestSuite; public class ParameterizedTest extends TestCase { private final int value; private int evilState; public static Collection<Object[]> parameters() { return Arrays.asList( new Object[] { 1 }, new Object[] { 2 }, new Object[] { -2 } ); } public ParameterizedTest(final int value) { this.value = value; } public void testMathPow() { final int square = value * value; final int powSquare = (int) Math.pow(value, 2) + evilState; assertEquals(square, powSquare); evilState++; } public void testIntDiv() { final int div = value / value; assertEquals(1, div); } public static Test suite() { return new ParameterizedTestSuite(ParameterizedTest.class, parameters()); } } </code></pre> <p>Note: the <code>evilState</code> variable is just here to show that all test instances are different as they should be, and that there is no shared state between them.</p>

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