tests: add additional tests for client ids (#212)

* tests: add additional tests for client ids

* fix: close Spanner to prevent resource leak

Author: olavloite

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

@@ -41,6 +41,7 @@
 import io.grpc.StatusRuntimeException;
 import io.grpc.inprocess.InProcessServerBuilder;
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
@@ -927,4 +928,36 @@ public void testBackendPartitionQueryOptions() {
       assertThat(request.getQueryOptions().getOptimizerVersion()).isEqualTo("1");
     }
   }
+
+  @Test
+  public void testClientIdReusedOnDatabaseNotFound() {
+    mockSpanner.setBatchCreateSessionsExecutionTime(
+        SimulatedExecutionTime.ofStickyException(
+            SpannerExceptionFactoryTest.newStatusResourceNotFoundException(
+                "my-database",
+                SpannerExceptionFactory.DATABASE_RESOURCE_TYPE,
+                "project/my-project/instances/my-instance/databases/my-database")));
+    try (Spanner spanner =
+        SpannerOptions.newBuilder()
+            .setProjectId("my-project")
+            .setChannelProvider(channelProvider)
+            .setCredentials(NoCredentials.getInstance())
+            .build()
+            .getService()) {
+      DatabaseId databaseId = DatabaseId.of("my-project", "my-instance", "my-database");
+      String prevClientId = null;
+      for (int i = 0; i < 100; i++) {
+        try {
+          DatabaseClientImpl client = (DatabaseClientImpl) spanner.getDatabaseClient(databaseId);
+          if (prevClientId != null) {
+            assertThat(client.clientId).isEqualTo(prevClientId);
+          }
+          prevClientId = client.clientId;
+          client.singleUse().readRow("MyTable", Key.of(0), Arrays.asList("MyColumn"));
+        } catch (Exception e) {
+          // ignore
+        }
+      }
+    }
+  }
 }

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

@@ -231,6 +231,13 @@ public void testClientId() throws Exception {
     assertThat(revalidated).isNotSameInstanceAs(databaseClient);
     assertThat(revalidated.clientId).isEqualTo(databaseClient.clientId);
 
+    // Now invalidate the second client and request a new one.
+    revalidated.pool.setResourceNotFoundException(
+        new DatabaseNotFoundException(DoNotConstructDirectly.ALLOWED, "not found", null, null));
+    DatabaseClientImpl revalidated2 = (DatabaseClientImpl) impl.getDatabaseClient(db);
+    assertThat(revalidated2).isNotSameInstanceAs(revalidated);
+    assertThat(revalidated2.clientId).isEqualTo(revalidated.clientId);
+
     // Create a new Spanner instance. This will generate new database clients with new ids.
     try (Spanner spanner =
         SpannerOptions.newBuilder()