Code review comment: ```suggestion     Supplier<Void> start = signal.waitForStart(Duration.standardMinutes(5)); ```

Code under review:
public void testSimpleInsertFlat() throws Exception {
    BeamSqlEnv sqlEnv =
        BeamSqlEnv.inMemory(new PubsubJsonTableProvider(), new BigQueryTableProvider());

    String createTableString =
        "CREATE EXTERNAL TABLE pubsub_topic (\n"
            + "event_timestamp TIMESTAMP, \n"
            + "id INTEGER, \n"
            + "name VARCHAR \n"
            + ") \n"
            + "TYPE 'pubsub' \n"
            + "LOCATION '"
            + pubsub.topicPath()
            + "' \n"
            + "TBLPROPERTIES '{ \"timestampAttributeKey\" : \"ts\" }'";
    sqlEnv.executeDdl(createTableString);

    String createTableStatement =
        "CREATE EXTERNAL TABLE bq_table( \n"
            + "   id BIGINT, \n"
            + "   name VARCHAR \n "
            + ") \n"
            + "TYPE 'bigquery' \n"
            + "LOCATION '"
            + bigQuery.tableSpec()
            + "'";
    sqlEnv.executeDdl(createTableStatement);

    String insertStatement =
        "INSERT INTO bq_table \n" + "SELECT \n" + "  id, \n" + "  name \n" + "FROM pubsub_topic";

    BeamSqlRelUtils.toPCollection(pipeline, sqlEnv.parseQuery(insertStatement));

    Supplier<Void> start = signal.waitForStart(Duration.standardMinutes(1));
    pipeline.apply(signal.signalStart());

    pipeline.run();

    
    start.get();

    List<PubsubMessage> messages =
        ImmutableList.of(
            message(ts(1), 3, "foo"), message(ts(2), 5, "bar"), message(ts(3), 7, "baz"));
    pubsub.publish(messages);

    bigQuery
        .assertThatAllRows(SOURCE_SCHEMA)
        .eventually(
            containsInAnyOrder(
                row(SOURCE_SCHEMA, 3L, "foo"),
                row(SOURCE_SCHEMA, 5L, "bar"),
                row(SOURCE_SCHEMA, 7L, "baz")))
        .pollFor(Duration.standardMinutes(5));
  }

Line commented on: Supplier<Void> start = signal.waitForStart(Duration.standardMinutes(1));

Revised code:
public void testSimpleInsertFlat() throws Exception {
    BeamSqlEnv sqlEnv =
        BeamSqlEnv.inMemory(new PubsubJsonTableProvider(), new BigQueryTableProvider());

    String createTableString =
        "CREATE EXTERNAL TABLE pubsub_topic (\n"
            + "event_timestamp TIMESTAMP, \n"
            + "id INTEGER, \n"
            + "name VARCHAR \n"
            + ") \n"
            + "TYPE 'pubsub' \n"
            + "LOCATION '"
            + pubsub.topicPath()
            + "' \n"
            + "TBLPROPERTIES '{ \"timestampAttributeKey\" : \"ts\" }'";
    sqlEnv.executeDdl(createTableString);

    String createTableStatement =
        "CREATE EXTERNAL TABLE bq_table( \n"
            + "   id BIGINT, \n"
            + "   name VARCHAR \n "
            + ") \n"
            + "TYPE 'bigquery' \n"
            + "LOCATION '"
            + bigQuery.tableSpec()
            + "'";
    sqlEnv.executeDdl(createTableStatement);

    String insertStatement =
        "INSERT INTO bq_table \n" + "SELECT \n" + "  id, \n" + "  name \n" + "FROM pubsub_topic";

    BeamSqlRelUtils.toPCollection(pipeline, sqlEnv.parseQuery(insertStatement));

    Supplier<Void> start = signal.waitForStart(Duration.standardMinutes(5));
    pipeline.apply(signal.signalStart());

    pipeline.run();

    
    start.get();

    List<PubsubMessage> messages =
        ImmutableList.of(
            message(ts(1), 3, "foo"), message(ts(2), 5, "bar"), message(ts(3), 7, "baz"));
    pubsub.publish(messages);

    bigQuery
        .assertThatAllRows(SOURCE_SCHEMA)
        .eventually(
            containsInAnyOrder(
                row(SOURCE_SCHEMA, 3L, "foo"),
                row(SOURCE_SCHEMA, 5L, "bar"),
                row(SOURCE_SCHEMA, 7L, "baz")))
        .pollFor(Duration.standardMinutes(5));
  }