Cleaned up and added to documentation of Paramterized to clarify vagu…

…e usecases. Added constructor to facilitate subclassing. Added test to clarify parameter inheritance.

src/main/java/org/junit/runners/Parameterized.java

@@ -55,7 +55,19 @@
  * <p>
  * Each instance of <code>FibonacciTest</code> will be constructed using the
  * two-argument constructor and the data values in the
- * <code>&#064;Parameters</code> method.
+ * <code>&#064;Parameters</code> method.  If multiple methods in a class or
+ * any of its superclasses are annotated:
+ * <ul>
+ * <li>Inherited methods do not need to be repeated, but may be overridden.</li>
+ * <li>The first one in a class file is given preference.</li>
+ * <li>Overridden inherited methods are given preference over declared
+ * methods.</li>
+ * <li>Declared methods are given preference over inherited methods 
+ * that have not been overridden.</li>
+ * </ul>
+ * 
+ * The <code>&#064;Parameters</code> method is
+ * called before any <code>&#064;BeforeClass</code> methods.
  * </p>
  */
 public class Parameterized extends Suite {
@@ -123,16 +135,29 @@ protected Statement classBlock(RunNotifier notifier) {
 	private final ArrayList<Runner> runners= new ArrayList<Runner>();
 
 	/**
-	 * Only called reflectively. Do not use programmatically.
+	 * Only called reflectively. Do not use programmatically. Initializes
+   * one runner for each test for each set of parameters.
 	 */
 	public Parameterized(Class<?> klass) throws Throwable {
-		super(klass, Collections.<Runner>emptyList());
+		this(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));
 	}
 
+  /**
+   * Called by this class and subclasses once the runners making 
+   * up the suite have been determined. Avoids runner initialization.
+   * 
+   * @param klass root of the suite
+   * @param runners for each class in the suite, a {@link Runner}
+   * @throws Throwable 
+   */
+  protected Parameterized(Class<?> klass, List<Runner> runners) throws Throwable {
+  	super(klass, runners);
+  }
+
 	@Override
 	protected List<Runner> getChildren() {
 		return runners;

src/test/java/org/junit/tests/running/classes/ParameterizedTestTest.java

@@ -78,6 +78,42 @@ public void plansNamedCorrectly() throws Exception {
 		assertEquals("[0]", description.getChildren().get(0).getDisplayName());
 	}
 
+	@RunWith(Parameterized.class)
+	static public class ExtendedParameters extends FibonacciTest {
+		public ExtendedParameters(int input, int expected) {
+			super(input, expected);
+		}
+	}
+
+	@Test
+	public void runsExtendedParametersClass() {
+		Result result= JUnitCore.runClasses(ExtendedParameters.class);
+		assertEquals(7, result.getRunCount());
+		assertEquals(6, result.getFailureCount());
+	}
+
+	@RunWith(Parameterized.class)
+	static public class OverriddenParameters extends FibonacciTest {
+		public OverriddenParameters(int input, int expected) {
+			super(input, expected);
+		}
+		@Parameters
+		public static Collection<Object[]> data() {
+			return Arrays.asList(new Object[][] { { 0, 0 }, { 1, 1 } });
+		}
+		@Parameters
+		public static Collection<Object[]> moreData() {
+			return Arrays.asList(new Object[][] { { 0, 0 }, { 1, 1 }, { 2, 1 } });
+		}
+	}
+
+	@Test
+	public void runsOverriddenParametersClass() {
+		Result result= JUnitCore.runClasses(OverriddenParameters.class);
+		assertEquals(2, result.getRunCount());
+		assertEquals(1, result.getFailureCount());
+	}
+
 	private static String fLog;
 
 	@RunWith(Parameterized.class)
@@ -132,6 +168,30 @@ public void validateClassCatchesNoParameters() {
 		assertEquals(1, result.getFailureCount());
 	}
 
+	@RunWith(Parameterized.class)
+	static public class MultipleParametersMethods {
+		@Test
+		public int test() {
+			return 0;
+		}
+
+		@Parameters
+		public static Collection<Object[]> data() {
+			return Arrays.asList(new Object[][] { { 0 } });
+		}
+
+		@Parameters
+		public static Collection<Object[]> moreData() {
+			return Arrays.asList(new Object[][] { { 0 }, { 0 } });
+		}
+	}
+
+	@Test
+	public void firstParametersMethodUsed() {
+		Result result= JUnitCore.runClasses(MultipleParametersMethods.class);
+		assertEquals(1, result.getRunCount());
+	}
+
 	@RunWith(Parameterized.class)
 	static public class IncorrectTest {
 		@Test