Add test rule which might fix github action unit test failure

Author: tejasd

firebase-perf/firebase-perf.gradle

@@ -138,4 +138,5 @@ dependencies {
     testImplementation libs.mockito.core
     testImplementation libs.mockito.mockito.inline
     testImplementation group: 'org.apache.httpcomponents', name: 'httpclient', version: '4.5.6'
+    testImplementation "androidx.arch.core:core-testing:2.1.0"
 }

firebase-perf/src/test/java/com/google/firebase/perf/transport/TransportManagerTest.java

@@ -28,6 +28,8 @@
 
 import android.content.Context;
 import android.content.pm.PackageInfo;
+
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule;
 import androidx.test.core.app.ApplicationProvider;
 import com.google.android.datatransport.TransportFactory;
 import com.google.android.gms.tasks.Tasks;
@@ -59,6 +61,7 @@
 import java.util.Map;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentCaptor;
@@ -88,6 +91,9 @@ public class TransportManagerTest extends FirebasePerformanceTestBase {
   @Mock private FlgTransport mockFlgTransport;
   @Captor private ArgumentCaptor<PerfMetric> perfMetricArgumentCaptor;
 
+  @Rule
+  public InstantTaskExecutorRule instantTaskExecutorRule = new InstantTaskExecutorRule();
+
   @Before
   public void setUp() {
     initMocks(this);