test: add a unit test for getTransaction

samples/system-test/spanner.test.js

@@ -825,25 +825,6 @@ describe('Autogenerated Admin Clients', () => {
     );
   });
 
-  // dml_standard_insert_transaction_using_getTransaction
-  it('should insert rows into an example table using getTransaction method', async () => {
-    const output = execSync(
-      `node insert-query-with-get-trasanction.js ${INSTANCE_ID} ${DATABASE_ID} ${PROJECT_ID}`
-    );
-    assert.match(
-      output,
-      /Successfully inserted 4 records into the Singers table/
-    );
-  });
-
-  // dml_standard_read_transaction_using_getTransaction
-  it('should query rows from an example table using getTransaction method', async () => {
-    const output = execSync(
-      `node read-query-with-get-transaction.js ${INSTANCE_ID} ${DATABASE_ID} ${PROJECT_ID}`
-    );
-    assert.strictEqual(output.length, 4);
-  });
-
   // dml_standard_insert
   it('should insert rows into an example table using a DML statement', async () => {
     const output = execSync(

test/spanner.ts

@@ -3286,6 +3286,22 @@
       });
     });
 
+    it('should use optimistic lock for getTransaction', async () => {
+      const database = newTestDatabase();
+      const promise = await database.getTransaction({optimisticLock: true});
+      const transaction = promise[0];
+      await transaction.run('SELECT 1').then(results => {
+        const request = spannerMock.getRequests().find(val => {
+          return (val as v1.ExecuteSqlRequest).sql;
+        }) as v1.ExecuteSqlRequest;
+        assert.ok(request, 'no ExecuteSqlRequest found');
+        assert.strictEqual(
+          request.transaction!.begin!.readWrite!.readLockMode,
+          'OPTIMISTIC'
+        );
+      });
+    });
+
     it('should reuse a session for optimistic and pessimistic locks', async () => {
       const database = newTestDatabase({min: 1, max: 1});
       let session1;