@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 testListTablesWithinNonexistentDB() {
    String dbName = "NONEXISTENT_DB";
    String schemaName = "NONEXISTENT_SCHEMA";
    assertThatExceptionOfType(RuntimeException.class)
        .isThrownBy(() -> catalog.listTables(Namespace.of(dbName, schemaName)))
        .withMessageContaining("does not exist")
        .withMessageContaining(dbName);
  }