Try to avoid intermittent test failure

hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/dao/BaseJpaTest.java

@@ -52,6 +52,7 @@
 import java.util.*;
 import java.util.concurrent.Callable;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import static ca.uhn.fhir.util.TestUtil.randomizeLocale;
@@ -431,6 +432,20 @@ public static void waitForSize(int theTarget, List<?> theList) {
 		}
 	}
 
+	public static void waitForTrue(Supplier<Boolean> theList) {
+		StopWatch sw = new StopWatch();
+		while (!theList.get() && sw.getMillis() <= 16000) {
+			try {
+				Thread.sleep(50);
+			} catch (InterruptedException theE) {
+				throw new Error(theE);
+			}
+		}
+		if (sw.getMillis() >= 16000) {
+			fail("Waited " + sw.toString() + " and is still false");
+		}
+	}
+
 	public static void waitForSize(int theTarget, Callable<Number> theCallable) throws Exception {
 		waitForSize(theTarget, 10000, theCallable);
 	}

hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/subscription/resthook/RestHookWithInterceptorR4Test.java

@@ -23,7 +23,8 @@
 import org.springframework.test.context.ContextConfiguration;
 
 import static org.hamcrest.Matchers.hasItem;
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
 
 /**
  * Test the rest-hook subscriptions
@@ -74,8 +75,9 @@ public void testBeforeRestHookDelivery_ModifyResourceId() throws Exception {
 		waitForSize(1, ourUpdatedObservations);
 		assertEquals(Constants.CT_FHIR_JSON_NEW, ourContentTypes.get(0));
 		assertEquals("Observation/A", ourUpdatedObservations.get(0).getId());
-		assertTrue(ourHitBeforeRestHookDelivery);
-		assertTrue(ourHitAfterRestHookDelivery);
+		// TODO: JA a latch would be even better but we'd need to allow customizable orders since the ad-hoc ones run first
+		waitForTrue(() -> ourHitBeforeRestHookDelivery);
+		waitForTrue(() -> ourHitAfterRestHookDelivery);
 	}
 
 	@Test
@@ -90,8 +92,9 @@ public void testBeforeRestHookDelivery_AddHeader() throws Exception {
 		waitForSize(0, ourCreatedObservations);
 		waitForSize(1, ourUpdatedObservations);
 		assertEquals(Constants.CT_FHIR_JSON_NEW, ourContentTypes.get(0));
-		assertTrue(ourHitBeforeRestHookDelivery);
-		assertTrue(ourHitAfterRestHookDelivery);
+		// TODO: JA a latch would be even better but we'd need to allow customizable orders since the ad-hoc ones run first
+		waitForTrue(() -> ourHitBeforeRestHookDelivery);
+		waitForTrue(() -> ourHitAfterRestHookDelivery);
 		assertThat(ourHeaders, hasItem("X-Foo: Bar"));
 	}