chore: address review comments

Author: olavloite

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerErrorInterceptor.java

@@ -72,8 +72,7 @@ public void start(Listener<RespT> responseListener, Metadata headers) {
               public void onClose(Status status, Metadata trailers) {
                 try {
                   // Translate INTERNAL errors that should be retried to a retryable error code.
-                  if (status.getCode() == Code.INTERNAL
-                      && IsRetryableInternalError.INSTANCE.isRetryableInternalError(status)) {
+                  if (IsRetryableInternalError.INSTANCE.isRetryableInternalError(status)) {
                     status =
                         Status.fromCode(Code.UNAVAILABLE).withDescription(status.getDescription());
                   }

google-cloud-spanner/src/test/java/com/google/cloud/spanner/RetryableInternalErrorTest.java

@@ -56,25 +56,34 @@ public void testTranslateInternalException() {
               Status.INTERNAL
                   .withDescription("Authentication backend internal server error. Please retry.")
                   .asRuntimeException()));
-      mockSpanner.setExecuteSqlExecutionTime(
-          SimulatedExecutionTime.ofException(
-              Status.INTERNAL
-                  .withDescription("Authentication backend internal server error. Please retry.")
-                  .asRuntimeException()));
 
+      // Execute a query. This will block until a BatchCreateSessions call has finished and then
+      // invoke ExecuteStreamingSql. Both of these RPCs should be retried.
       try (ResultSet resultSet = client.singleUse().executeQuery(SELECT1_STATEMENT)) {
         assertTrue(resultSet.next());
         assertFalse(resultSet.next());
       }
+      // Verify that both the BatchCreateSessions call and the ExecuteStreamingSql call were
+      // retried.
+      assertEquals(2, mockSpanner.countRequestsOfType(BatchCreateSessionsRequest.class));
+      assertEquals(2, mockSpanner.countRequestsOfType(ExecuteSqlRequest.class));
+      // Clear the requests before the next test.
+      mockSpanner.clearRequests();
+
+      // Execute a DML statement. This uses the ExecuteSql RPC.
+      assertEquals(0, mockSpanner.countRequestsOfType(ExecuteSqlRequest.class));
+      mockSpanner.setExecuteSqlExecutionTime(
+          SimulatedExecutionTime.ofException(
+              Status.INTERNAL
+                  .withDescription("Authentication backend internal server error. Please retry.")
+                  .asRuntimeException()));
       assertEquals(
           Long.valueOf(1L),
           client
               .readWriteTransaction()
               .run(transaction -> transaction.executeUpdate(INSERT_STATEMENT)));
-
-      // Verify that all the RPCs were retried.
-      assertEquals(2, mockSpanner.countRequestsOfType(BatchCreateSessionsRequest.class));
-      assertEquals(4, mockSpanner.countRequestsOfType(ExecuteSqlRequest.class));
+      // Verify that also this request was retried.
+      assertEquals(2, mockSpanner.countRequestsOfType(ExecuteSqlRequest.class));
     }
   }
 }