@Override
  public List<TableIdentifier> listTables(Namespace namespace) {
    SnowflakeIdentifier scope = NamespaceHelpers.toSnowflakeIdentifier(namespace);
    Preconditions.checkArgument(
        scope.type() == SnowflakeIdentifier.Type.SCHEMA,
        "listTables must be at SCHEMA level; got %s from namespace %s",
        scope,
        namespace);

    List<SnowflakeIdentifier> sfTables = snowflakeClient.listIcebergTables(scope);

    return sfTables.stream()
        .map(NamespaceHelpers::toIcebergTableIdentifier)
        .collect(Collectors.toList());
  }
@Test
  public void testListTablesWithinDB() {
    String dbName = "DB_1";
    assertThatExceptionOfType(IllegalArgumentException.class)
        .isThrownBy(() -> catalog.listTables(Namespace.of(dbName)))
        .withMessageContaining("listTables must be at SCHEMA level");
  }