Flaky io.trino.plugin.memory.TestMemoryConnectorTest.testCreateAndDropTable

[phd3]

2021-08-30T16:11:41.0365211Z [ERROR] testCreateAndDropTable(io.trino.plugin.memory.TestMemoryConnectorTest)  Time elapsed: 0.007 s  <<< FAILURE!
2021-08-30T16:11:41.0370318Z java.lang.AssertionError: expected [7] but found [8]
2021-08-30T16:11:41.0374137Z 	at org.testng.Assert.fail(Assert.java:94)
2021-08-30T16:11:41.0399162Z 	at org.testng.Assert.failNotEquals(Assert.java:513)
2021-08-30T16:11:41.0404045Z 	at org.testng.Assert.assertEqualsImpl(Assert.java:135)
2021-08-30T16:11:41.0408727Z 	at org.testng.Assert.assertEquals(Assert.java:116)
2021-08-30T16:11:41.0413206Z 	at org.testng.Assert.assertEquals(Assert.java:389)
2021-08-30T16:11:41.0417648Z 	at org.testng.Assert.assertEquals(Assert.java:399)
2021-08-30T16:11:41.0426071Z 	at io.trino.plugin.memory.TestMemoryConnectorTest.testCreateAndDropTable(TestMemoryConnectorTest.java:125)
2021-08-30T16:11:41.0433699Z 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
2021-08-30T16:11:41.0441950Z 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
2021-08-30T16:11:41.0451108Z 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2021-08-30T16:11:41.0457123Z 	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
2021-08-30T16:11:41.0528685Z 	at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:104)
2021-08-30T16:11:41.0534737Z 	at org.testng.internal.Invoker.invokeMethod(Invoker.java:645)
2021-08-30T16:11:41.0540527Z 	at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:851)
2021-08-30T16:11:41.0546447Z 	at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1177)
2021-08-30T16:11:41.0553561Z 	at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:129)
2021-08-30T16:11:41.0559901Z 	at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:112)
2021-08-30T16:11:41.0567549Z 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
2021-08-30T16:11:41.0626071Z 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
2021-08-30T16:11:41.0628481Z 	at java.base/java.lang.Thread.run(Thread.java:829)

https://github.com/trinodb/trino/runs/3463395818?check_suite_focus=true

[ebyhr]

It seems the test verifies table count before and after the operation. It will fail if other tests create or drop a table at the same time.

    @Test
    public void testCreateAndDropTable()
    {
        int tablesBeforeCreate = listMemoryTables().size();
        assertUpdate("CREATE TABLE test AS SELECT * FROM tpch.tiny.nation", "SELECT count(*) FROM nation");
        assertEquals(listMemoryTables().size(), tablesBeforeCreate + 1);

        assertUpdate("DROP TABLE test");
        assertEquals(listMemoryTables().size(), tablesBeforeCreate);
    }

[hashhar]

@ebyhr Looks like it should be easy to rewrite to use SHOW TABLES to verify table existence to avoid this problem?

Are you already working on this? If not, I'll send a PR.

[ebyhr]

@hashhar I'm not working on this. Please feel free to send PR. Thanks.

[findepi]

Thanks @hashhar for fixing this!