fixes #875

Fixes #875

In versions 4.7 through 4.11 setting up a Timeout @rule with a value of
0 would result in no timeout. In 4.12 FailOnTimeout switched to using
FutureTask.get(timeout). That method treats non-positive timeouts to
mean "timeout right now".

This fix checks that the timeout value is positive before using it,
and otherwise will wait indefinitely.

src/main/java/org/junit/internal/runners/statements/FailOnTimeout.java

@@ -55,7 +55,11 @@ public void evaluate() throws Throwable {
      */
     private Throwable getResult(FutureTask<Throwable> task, Thread thread) {
         try {
-            return task.get(fTimeout, fTimeUnit);
+            if (fTimeout > 0) {
+                return task.get(fTimeout, fTimeUnit);
+            } else {
+                return task.get();
+            }
         } catch (InterruptedException e) {
             return e; // caller will re-throw; no need to call Thread.interrupt()
         } catch (ExecutionException e) {

src/main/java/org/junit/rules/Timeout.java

@@ -30,6 +30,10 @@
  * the test completes, its execution is interrupted via {@link Thread#interrupt()}.
  * This happens in interruptable I/O and locks, and methods in {@link Object}
  * and {@link Thread} throwing {@link InterruptedException}.
+ * <p>
+ * A specified timeout of 0 will be interpreted as not set, however tests will
+ * still launch from separate threads. This can be useful for disabling timeouts
+ * in environments where they are dynamically set based on some property.
  *
  * @since 4.7
  */

src/test/java/org/junit/tests/running/methods/TimeoutTest.java

@@ -274,4 +274,26 @@ public void makeSureAfterIsCalledAfterATimeout() {
         JUnitCore.runClasses(WillTimeOut.class);
         assertThat(WillTimeOut.afterWasCalled, is(true));
     }
+
+    public static class TimeOutZero {
+        @Rule
+        public Timeout timeout = Timeout.seconds(0);
+
+        @Test
+        public void test() {
+            try {
+                Thread.sleep(200); // long enough to suspend thread execution
+            } catch (InterruptedException e) {
+                // Don't care
+            }
+        }
+    }
+
+    @Test
+    public void testZeroTimeoutIsIgnored() {
+        JUnitCore core = new JUnitCore();
+        Result result = core.run(TimeOutZero.class);
+        assertEquals("Should run the test", 1, result.getRunCount());
+        assertEquals("Test should not have failed", 0, result.getFailureCount());
+    }
 }