--- jsr166/src/test/tck/JSR166TestCase.java	2019/07/28 18:09:25	1.255
+++ jsr166/src/test/tck/JSR166TestCase.java	2019/08/20 23:06:11	1.258
@@ -685,6 +685,20 @@ public class JSR166TestCase extends Test
     static TimeUnit randomTimeUnit() { return RANDOM_TIMEUNIT; }
 
     /**
+     * Returns a random boolean; a "coin flip".
+     */
+    static boolean randomBoolean() {
+        return ThreadLocalRandom.current().nextBoolean();
+    }
+
+    /**
+     * Returns a random element from given choices.
+     */
+    <T> T chooseRandomly(T... choices) {
+        return choices[ThreadLocalRandom.current().nextInt(choices.length)];
+    }
+
+    /**
      * Returns the shortest timed delay. This can be scaled up for
      * slow machines using the jsr166.delay.factor system property,
      * or via jtreg's -timeoutFactor: flag.
@@ -1367,6 +1381,20 @@ public class JSR166TestCase extends Test
     }
 
     /**
+     * Spin-waits up to LONG_DELAY_MS milliseconds for the current thread to
+     * be interrupted.  Clears the interrupt status before returning.
+     */
+    void awaitInterrupted() {
+        for (long startTime = 0L; !Thread.interrupted(); ) {
+            if (startTime == 0L)
+                startTime = System.nanoTime();
+            else if (millisElapsedSince(startTime) > LONG_DELAY_MS)
+                fail("timed out waiting for thread interrupt");
+            Thread.yield();
+        }
+    }
+
+    /**
      * Returns the number of milliseconds since time given by
      * startNanoTime, which must have been previously returned from a
      * call to {@link System#nanoTime()}.
@@ -1427,11 +1455,12 @@ public class JSR166TestCase extends Test
             t.join(timeoutMillis);
         } catch (InterruptedException fail) {
             threadUnexpectedException(fail);
-        } finally {
-            if (t.getState() != Thread.State.TERMINATED) {
-                t.interrupt();
-                threadFail("timed out waiting for thread to terminate");
-            }
+        }
+	Thread.State state;
+	if ((state = t.getState()) != Thread.State.TERMINATED) {
+	    t.interrupt();
+	    threadFail("timed out waiting for thread to terminate; "
+		       + "state=" + state);
         }
     }