Add stack traces to RetentionLeasesIT failures

Today `RetentionLeaseIT` calls `fail(e.toString())` on some exceptions, losing
the stack trace that came with the exception. This commit adjusts this to
re-throw the exception wrapped in an `AssertionError` so we can see more
details about failures such as elastic#41430.

Author: DaveCTurner

server/src/test/java/org/elasticsearch/index/seqno/RetentionLeaseIT.java

@@ -108,7 +108,7 @@ public void testRetentionLeasesSyncedOnAdd() throws Exception {
             final long retainingSequenceNumber = randomLongBetween(0, Long.MAX_VALUE);
             final String source = randomAlphaOfLength(8);
             final CountDownLatch latch = new CountDownLatch(1);
-            final ActionListener<ReplicationResponse> listener = ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString()));
+            final ActionListener<ReplicationResponse> listener = countDownLatchListener(latch);
             // simulate a peer recovery which locks the soft deletes policy on the primary
             final Closeable retentionLock = randomBoolean() ? primary.acquireRetentionLock() : () -> {};
             currentRetentionLeases.put(id, primary.addRetentionLease(id, retainingSequenceNumber, source, listener));
@@ -155,7 +155,7 @@ public void testRetentionLeaseSyncedOnRemove() throws Exception {
             final long retainingSequenceNumber = randomLongBetween(0, Long.MAX_VALUE);
             final String source = randomAlphaOfLength(8);
             final CountDownLatch latch = new CountDownLatch(1);
-            final ActionListener<ReplicationResponse> listener = ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString()));
+            final ActionListener<ReplicationResponse> listener = countDownLatchListener(latch);
             // simulate a peer recovery which locks the soft deletes policy on the primary
             final Closeable retentionLock = randomBoolean() ? primary.acquireRetentionLock() : () -> {};
             currentRetentionLeases.put(id, primary.addRetentionLease(id, retainingSequenceNumber, source, listener));
@@ -166,7 +166,7 @@ public void testRetentionLeaseSyncedOnRemove() throws Exception {
         for (int i = 0; i < length; i++) {
             final String id = randomFrom(currentRetentionLeases.keySet());
             final CountDownLatch latch = new CountDownLatch(1);
-            primary.removeRetentionLease(id, ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString())));
+            primary.removeRetentionLease(id, countDownLatchListener(latch));
             // simulate a peer recovery which locks the soft deletes policy on the primary
             final Closeable retentionLock = randomBoolean() ? primary.acquireRetentionLock() : () -> {};
             currentRetentionLeases.remove(id);
@@ -228,7 +228,7 @@ public void testRetentionLeasesSyncOnExpiration() throws Exception {
             final long retainingSequenceNumber = randomLongBetween(0, Long.MAX_VALUE);
             final String source = randomAlphaOfLength(8);
             final CountDownLatch latch = new CountDownLatch(1);
-            final ActionListener<ReplicationResponse> listener = ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString()));
+            final ActionListener<ReplicationResponse> listener = countDownLatchListener(latch);
             final RetentionLease currentRetentionLease = primary.addRetentionLease(id, retainingSequenceNumber, source, listener);
             final long now = System.nanoTime();
             latch.await();
@@ -390,7 +390,7 @@ public void testRetentionLeasesSyncOnRecovery() throws Exception {
             final long retainingSequenceNumber = randomLongBetween(0, Long.MAX_VALUE);
             final String source = randomAlphaOfLength(8);
             final CountDownLatch latch = new CountDownLatch(1);
-            final ActionListener<ReplicationResponse> listener = ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString()));
+            final ActionListener<ReplicationResponse> listener = countDownLatchListener(latch);
             currentRetentionLeases.put(id, primary.addRetentionLease(id, retainingSequenceNumber, source, listener));
             latch.await();
             currentRetentionLeases.put(id, primary.renewRetentionLease(id, retainingSequenceNumber, source));
@@ -479,7 +479,7 @@ public void testCanRenewRetentionLeaseUnderBlock() throws InterruptedException {
                          */
                         assertBusy(() -> assertThat(primary.loadRetentionLeases().leases(), contains(retentionLease.get())));
                     } catch (final Exception e) {
-                        fail(e.toString());
+                        failWithException(e);
                     }
                 });
 
@@ -516,7 +516,7 @@ private void runUnderBlockTest(
 
         final String source = randomAlphaOfLength(8);
         final CountDownLatch latch = new CountDownLatch(1);
-        final ActionListener<ReplicationResponse> listener = ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString()));
+        final ActionListener<ReplicationResponse> listener = countDownLatchListener(latch);
         primary.addRetentionLease(idForInitialRetentionLease, initialRetainingSequenceNumber, source, listener);
         latch.await();
 
@@ -545,7 +545,7 @@ public void onResponse(final ReplicationResponse replicationResponse) {
 
                         @Override
                         public void onFailure(final Exception e) {
-                            fail(e.toString());
+                            failWithException(e);
                         }
 
                     });
@@ -598,7 +598,7 @@ public void testCanRenewRetentionLeaseWithoutWaitingForShards() throws Interrupt
                          */
                         assertBusy(() -> assertThat(primary.loadRetentionLeases().leases(), contains(retentionLease.get())));
                     } catch (final Exception e) {
-                        fail(e.toString());
+                        failWithException(e);
                     }
                 });
 
@@ -637,7 +637,7 @@ private void runWaitForShardsTest(
 
         final String source = randomAlphaOfLength(8);
         final CountDownLatch latch = new CountDownLatch(1);
-        final ActionListener<ReplicationResponse> listener = ActionListener.wrap(r -> latch.countDown(), e -> fail(e.toString()));
+        final ActionListener<ReplicationResponse> listener = countDownLatchListener(latch);
         primary.addRetentionLease(idForInitialRetentionLease, initialRetainingSequenceNumber, source, listener);
         latch.await();
 
@@ -665,7 +665,7 @@ public void onResponse(final ReplicationResponse replicationResponse) {
 
                     @Override
                     public void onFailure(final Exception e) {
-                        fail(e.toString());
+                        failWithException(e);
                     }
 
                 });
@@ -674,4 +674,12 @@ public void onFailure(final Exception e) {
         afterSync.accept(primary);
     }
 
+    private static void failWithException(Exception e) {
+        throw new AssertionError("unexpected", e);
+    }
+
+    private static ActionListener<ReplicationResponse> countDownLatchListener(CountDownLatch latch) {
+        return ActionListener.wrap(r -> latch.countDown(), RetentionLeaseIT::failWithException);
+    }
+
 }