public BigtableRowToBeamRowFlat(Schema schema, Map<String, Set<String>> columnsMapping) {
    this.schema = schema;
    this.columnsMapping = columnsMapping;
  }
@Test
  public void testBigtableRowToBeamRowFlat() {
    Map<String, Set<String>> columnsMapping =
        ImmutableMap.of(
            FAMILY_TEST, ImmutableSet.of(BOOL_COLUMN, LONG_COLUMN, STRING_COLUMN, DOUBLE_COLUMN));

    PCollection<Row> rows =
        pipeline
            .apply(Create.of(bigtableRow(1), bigtableRow(2)))
            .setCoder(ProtoCoder.of(TypeDescriptor.of(com.google.bigtable.v2.Row.class)))
            .apply(new BigtableRowToBeamRowFlat(TEST_FLAT_SCHEMA, columnsMapping))
            .setRowSchema(TEST_FLAT_SCHEMA);

    PAssert.that(rows).containsInAnyOrder(row(1), row(2));
    pipeline.run().waitUntilFinish();
  }