build: fix auth library native tests and flaky test (#12881)

The `google-auth-library-java` migration to the monorepo inadvertently
enabled GraalVM native testing for the credentials module because the
generic `graalvm-single` job type runs tests on all modules in the
subdirectory. In the original repository, this job was scoped to only
test the `oauth2_http` module.

This change adds `<skipNativeTests>true</skipNativeTests>` to the
credentials and appengine module POMs to skip native tests, resolving
the failure when the plugin cannot find test configuration files. It
also stabilizes a flaky concurrent test in cab-token-generator.

Fixes #12859

Author: meltsufin

.kokoro/presubmit/google-auth-library-java-graalvm-native-presubmit.cfg

@@ -50,3 +50,9 @@ env_vars: {
   key: "BUILD_SUBDIR"
   value: "google-auth-library-java"
 }
+
+env_vars: {
+  key: "INTEGRATION_TEST_ARGS"
+  value: "-Pslf4j2x"
+}
+

google-auth-library-java/appengine/pom.xml

@@ -42,6 +42,14 @@
           </archive> 
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.graalvm.buildtools</groupId>
+        <artifactId>native-maven-plugin</artifactId>
+        <configuration>
+          <skipNativeTests>true</skipNativeTests>
+        </configuration>
+      </plugin>
+
     </plugins>
   </build>
 

google-auth-library-java/cab-token-generator/javatests/com/google/auth/credentialaccessboundary/ClientSideCredentialAccessBoundaryFactoryTest.java

@@ -614,22 +614,28 @@ private Clock createMockClock(RefreshType refreshType, GoogleCredentials sourceC
         // Set mocked time so that the token is fresh and no refresh is needed (before the refresh
         // margin).
         mockedTimeInMillis = expirationTimeInMillis - refreshMarginInMillis - 60000;
+        when(mockClock.currentTimeMillis()).thenReturn(mockedTimeInMillis);
         break;
       case ASYNC:
         // Set mocked time so that the token is nearing expiry and an async refresh is triggered
         // (within the refresh margin).
         mockedTimeInMillis = expirationTimeInMillis - refreshMarginInMillis + 60000;
+        when(mockClock.currentTimeMillis())
+            .thenReturn(
+                mockedTimeInMillis, // First call: Stale (triggers the async refresh)
+                currentTimeInMillis // Subsequent calls: Fresh (skips redundant refreshes)
+                );
         break;
       case BLOCKING:
         // Set mocked time so that the token requires immediate refresh (just after the minimum
         // token lifetime).
         mockedTimeInMillis = expirationTimeInMillis - minimumTokenLifetimeMillis + 60000;
+        when(mockClock.currentTimeMillis()).thenReturn(mockedTimeInMillis);
         break;
       default:
         throw new IllegalArgumentException("Unexpected RefreshType: " + refreshType);
     }
 
-    when(mockClock.currentTimeMillis()).thenReturn(mockedTimeInMillis);
     return mockClock;
   }
 

google-auth-library-java/credentials/pom.xml

@@ -22,6 +22,13 @@
     <sourceDirectory>java</sourceDirectory>
     <testSourceDirectory>javatests</testSourceDirectory>
     <plugins>
+      <plugin>
+        <groupId>org.graalvm.buildtools</groupId>
+        <artifactId>native-maven-plugin</artifactId>
+        <configuration>
+          <skipNativeTests>true</skipNativeTests>
+        </configuration>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-source-plugin</artifactId>