def test_estimate_statement_invalid_syntax(self):
"""
DB Eng Specs (postgres): Test estimate_statement_cost invalid syntax
"""
from psycopg2 import errors
cursor = mock.Mock()
cursor.execute.side_effect = errors.SyntaxError("""
syntax error at or near "EXPLAIN"
LINE 1: EXPLAIN DROP TABLE birth_names
^
""")
sql = "DROP TABLE birth_names"
with self.assertRaises(errors.SyntaxError):
PostgresEngineSpec.estimate_statement_cost(sql, cursor)
def test_estimate_statement_cost_select_star(self):
"""
DB Eng Specs (postgres): Test estimate_statement_cost select star
"""
cursor = mock.Mock()
cursor.fetchone.return_value = (
"Seq Scan on birth_names (cost=0.00..1537.91 rows=75691 width=46)",
)
sql = "SELECT * FROM birth_names"
results = PostgresEngineSpec.estimate_statement_cost(sql, cursor)
self.assertEqual(
results, {"Start-up cost": 0.00, "Total cost": 1537.91,},
)
