chore: minor test cleanup (#726)

Author: igorbernstein2

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/admin/v2/it/BigtableBackupIT.java

@@ -43,7 +43,7 @@
 import com.google.cloud.bigtable.test_helpers.env.EmulatorEnv;
 import com.google.cloud.bigtable.test_helpers.env.TestEnvRule;
 import com.google.common.collect.Lists;
-import com.google.protobuf.Timestamp;
+import com.google.protobuf.ByteString;
 import io.grpc.StatusRuntimeException;
 import java.io.IOException;
 import java.util.List;
@@ -119,7 +119,7 @@ public static void createClient()
  ApiFuture<Void> future =
  dataClient.mutateRowAsync(
  RowMutation.create(testTable.getId(), "test-row-" + i)
- .setCell("cf1", "", rowBytes.toString()));
+ .setCell("cf1", ByteString.EMPTY, ByteString.copyFrom(rowBytes)));
  futures.add(future);
  }
  ApiFutures.allAsList(futures).get(3, TimeUnit.MINUTES);
@@ -188,7 +188,7 @@ public void createAndGetBackupTest() throws InterruptedException {
  .isEqualTo(expireTime);
  assertWithMessage("Got empty start time in GetBackup API")
  .that(result.getStartTime())
- .isNotEqualTo(Timestamp.getDefaultInstance());
+ .isNotNull();
  assertWithMessage("Got wrong size bytes in GetBackup API")
  .that(result.getSizeBytes())
  .isEqualTo(0L);

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/data/v2/BigtableDataSettingsTest.java

@@ -19,7 +19,10 @@
 
 import com.google.cloud.bigtable.data.v2.stub.EnhancedBigtableStubSettings;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
 
+@RunWith(JUnit4.class)
 public class BigtableDataSettingsTest {
 
  @Test