add verification to reproduce exception

Author: mpeddada1

gax-java/gax/src/main/java/com/google/api/gax/rpc/internal/QuotaProjectIdHidingCredentials.java

@@ -90,8 +90,8 @@ public void refresh() throws IOException {
     this.wrappedCredentials.refresh();
   }
 
-  @Override
-  public String getUniverseDomain() throws IOException {
-    return this.wrappedCredentials.getUniverseDomain();
-  }
+  // @Override
+  // public String getUniverseDomain() throws IOException {
+  //   return this.wrappedCredentials.getUniverseDomain();
+  // }
 }

showcase/gapic-showcase/src/test/java/com/google/showcase/v1beta1/it/ITEndpointContext.java

@@ -444,4 +444,29 @@ void endpointResolution_builderBuilderBackToBuilder() throws IOException {
     echoStubSettingsBuilder = echoStubSettings.toBuilder();
     Truth.assertThat(echoStubSettingsBuilder.getEndpoint()).isEqualTo(customEndpoint);
   }
+
+  @Test
+  void universeDomainValidation_quotaProjectId_credentialsNonGDUMatchesUserConfiguration()
+      throws IOException {
+    String universeDomain = "random.com";
+    EchoSettings echoSettings =
+        ExtendedEchoSettings.newBuilder()
+            .setQuotaProjectId("exampleProject")
+            .setCredentialsProvider(UniverseDomainCredentialsProvider.create(universeDomain))
+            .setEndpoint(TestClientInitializer.DEFAULT_GRPC_ENDPOINT)
+            .setUniverseDomain(universeDomain)
+            .setTransportChannelProvider(
+                EchoSettings.defaultGrpcTransportProviderBuilder()
+                    .setChannelConfigurator(ManagedChannelBuilder::usePlaintext)
+                    .build())
+            .build();
+    echoClient = EchoClient.create(echoSettings);
+
+    UnauthenticatedException exception =
+        assertThrows(UnauthenticatedException.class, () -> echoClient.echo(DEFAULT_REQUEST));
+    Truth.assertThat(exception.getMessage())
+        .contains(
+            "The configured universe domain (random.com) does not match the universe domain found in the credentials (googleapis.com).");
+    // Truth.assertThat(echoClient.echo(DEFAULT_REQUEST).getContent()).isEqualTo("echo");
+  }
 }