IGNITE-23581 Fix ItMetastorageGroupDisasterRecoveryTest#oldMgLeaderDo…

…esNotHijackLeadership() (apache#4661)

* Make sure Metastorage does not diverge in this test (it's an unrelated matter)
* Include stack trace info in a failed assertion description

modules/core/src/testFixtures/java/org/apache/ignite/internal/testframework/matchers/CompletableFutureExceptionMatcher.java

@@ -26,6 +26,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import org.apache.ignite.internal.util.ExceptionUtils;
 import org.hamcrest.Description;
 import org.hamcrest.Matcher;
 import org.hamcrest.TypeSafeMatcher;
@@ -106,7 +107,7 @@ protected void describeMismatchSafely(CompletableFuture<?> item, Description mis
             try {
                 item.join();
             } catch (Exception e) {
-                mismatchDescription.appendText("was completed exceptionally with ").appendValue(unwrapCause(e));
+                mismatchDescription.appendText("was completed exceptionally with ").appendValue(describeThrowable(unwrapCause(e)));
             }
         } else if (item.isDone()) {
             mismatchDescription.appendText("was completed successfully");
@@ -115,6 +116,10 @@ protected void describeMismatchSafely(CompletableFuture<?> item, Description mis
         }
     }
 
+    private static String describeThrowable(Throwable throwable) {
+        return throwable.toString() + ", stack trace " + ExceptionUtils.getFullStackTrace(throwable);
+    }
+
     private boolean matchesWithCause(Throwable e) {
         for (Throwable current = e; current != null; current = current.getCause()) {
             if (matchesException(current) || Arrays.stream(current.getSuppressed()).anyMatch(this::matchesWithCause)) {

modules/system-disaster-recovery/src/integrationTest/java/org/apache/ignite/internal/disaster/system/ItMetastorageGroupDisasterRecoveryTest.java

@@ -209,13 +209,12 @@ void oldMgLeaderDoesNotHijackLeadership() throws Exception {
         startAndInitCluster(2, new int[]{0}, new int[]{1});
         waitTillClusterStateIsSavedToVaultOnConductor(0);
 
-        // This makes the MG majority go away.
-        cluster.stopNode(1);
-
-        IgniteImpl igniteImpl0BeforeRestart = igniteImpl(0);
-
-        assertThatMgHasNoMajority(igniteImpl0BeforeRestart);
+        // Copy Metastorage state from old leader (1) to future leader (0) to make sure that 1 is not ahead of 0 and there will be
+        // no Metastorage divergence when we make 0 new leader and migrate 1 to cluster again.
+        // This stops both nodes.
+        makeSure2NodesHaveSameMetastorageState(1, 0);
 
+        cluster.startEmbeddedNode(0);
         initiateMgRepairVia(0, 1, 0);
 
         IgniteImpl restartedIgniteImpl0 = waitTillNodeRestartsInternally(0);
@@ -257,14 +256,10 @@ void migratesNodesThatSawNoReparationToNewClusterIfMetastorageDidNotDiverge() th
         startAndInitCluster(2, new int[]{0}, new int[]{1});
         waitTillClusterStateIsSavedToVaultOnConductor(0);
 
-        ComponentWorkingDir msWorkDir0 = igniteImpl(0).metastorageWorkDir();
-        ComponentWorkingDir msWorkDir1 = igniteImpl(1).metastorageWorkDir();
-
-        IntStream.of(0, 1).parallel().forEach(cluster::stopNode);
-
         // Copy Metastorage state from old leader (1) to future leader (0) to make sure that 1 is not ahead of 0 and there will be
         // no Metastorage divergence when we make 0 new leader and migrate 1 to cluster again.
-        copyMetastorageState(msWorkDir1, msWorkDir0);
+        // This stops both nodes.
+        makeSure2NodesHaveSameMetastorageState(1, 0);
 
         // Repair MG with just node 0 in CMG.
         cluster.startEmbeddedNode(0);
@@ -279,6 +274,15 @@ void migratesNodesThatSawNoReparationToNewClusterIfMetastorageDidNotDiverge() th
         assertTopologyContainsNode(1, topologySnapshot);
     }
 
+    private void makeSure2NodesHaveSameMetastorageState(int leaderIndex, int followerIndex) throws IOException {
+        ComponentWorkingDir followerMsWorkDir = igniteImpl(followerIndex).metastorageWorkDir();
+        ComponentWorkingDir leaderMsWorkDir = igniteImpl(leaderIndex).metastorageWorkDir();
+
+        IntStream.of(followerIndex, leaderIndex).parallel().forEach(cluster::stopNode);
+
+        copyMetastorageState(leaderMsWorkDir, followerMsWorkDir);
+    }
+
     private static void copyMetastorageState(ComponentWorkingDir source, ComponentWorkingDir dest) throws IOException {
         replaceDir(source.dbPath(), dest.dbPath());
         replaceDir(source.raftLogPath(), dest.raftLogPath());