"""Unit tests for SequenceHealthCalc, specifically _parse_sequence_name parsing."""
import pytest
from postgres_mcp.database_health.sequence_health_calc import SequenceHealthCalc
class TestParseSequenceName:
"""Tests for _parse_sequence_name method."""
@pytest.fixture
def calc(self):
"""Create a SequenceHealthCalc instance with a mock driver."""
# We only need the instance for calling _parse_sequence_name
# which doesn't use the sql_driver
return SequenceHealthCalc(sql_driver=None) # type: ignore[arg-type]
def test_simple_sequence(self, calc):
"""Parse simple unquoted sequence name."""
schema, name = calc._parse_sequence_name("nextval('my_seq'::regclass)")
assert schema == "public"
assert name == "my_seq"
def test_sequence_with_schema(self, calc):
"""Parse sequence with explicit schema."""
schema, name = calc._parse_sequence_name("nextval('myschema.my_seq'::regclass)")
assert schema == "myschema"
assert name == "my_seq"
def test_uppercase_sequence(self, calc):
"""Parse uppercase sequence name (quoted in PostgreSQL)."""
schema, name = calc._parse_sequence_name("nextval('\"UpperCaseSeq\"'::regclass)")
assert schema == "public"
assert name == "UpperCaseSeq"
def test_uppercase_with_schema(self, calc):
"""Parse uppercase sequence with schema."""
schema, name = calc._parse_sequence_name('nextval(\'"MySchema"."MySeq"\'::regclass)')
assert schema == "MySchema"
assert name == "MySeq"
def test_text_cast_format(self, calc):
"""Parse sequence with text cast format."""
schema, name = calc._parse_sequence_name("nextval(('my_seq'::text)::regclass)")
assert schema == "public"
assert name == "my_seq"
def test_serial_sequence_naming(self, calc):
"""Parse auto-generated SERIAL sequence name."""
schema, name = calc._parse_sequence_name("nextval('users_id_seq'::regclass)")
assert schema == "public"
assert name == "users_id_seq"
def test_uppercase_table_serial(self, calc):
"""Parse sequence from uppercase table with SERIAL column."""
# PostgreSQL generates: "TableName_column_seq"
schema, name = calc._parse_sequence_name("nextval('\"UpperCaseOrders_id_seq\"'::regclass)")
assert schema == "public"
assert name == "UpperCaseOrders_id_seq"
# Known limitation: sequence names containing dots
# This test documents the current behavior (which is incorrect for this edge case)
@pytest.mark.xfail(reason="Known limitation: dots in sequence names not supported")
def test_sequence_name_with_dot(self, calc):
"""Sequence names containing dots are not correctly parsed.
This is a known limitation. In PostgreSQL, you can have a sequence
named "my.seq" (with a literal dot), which would be stored as:
nextval('"my.seq"'::regclass)
The current parser incorrectly splits this as schema="my", name="seq".
"""
schema, name = calc._parse_sequence_name("nextval('\"my.seq\"'::regclass)")
assert schema == "public"
assert name == "my.seq"
