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ThothII/harness/tests/l0/test_db_sampling.py

84 lines
3.2 KiB
Python

"""L0: db/sampling against known data (testcontainers).
Verifies unique_values_for_lsh returns the expected most-frequent values for text
columns, and that wide_text / non-text columns are excluded.
"""
import pytest
from tht.config import LshConfig
from tht.db.introspect import introspect
from tht.db.sampling import distinct_values, is_text_type, sample_column, unique_values_for_lsh
pytestmark = [pytest.mark.l0]
@pytest.mark.parametrize("invalid_limit", [True, 1.5, 0, -1])
def test_direct_sampling_rejects_non_positive_integer_limits(admin_engine, invalid_limit):
with pytest.raises(ValueError, match="positive integer"):
sample_column(
admin_engine, "dw", "fct_ricoveri", "reparto", limit=invalid_limit
)
with pytest.raises(ValueError, match="positive integer"):
distinct_values(
admin_engine,
"dw",
"fct_ricoveri",
"reparto",
max_values=invalid_limit,
)
def test_is_text_type():
assert is_text_type("text")
assert is_text_type("varchar(100)")
assert is_text_type("character varying")
assert not is_text_type("integer")
assert not is_text_type("bigint")
assert not is_text_type("timestamp without time zone")
def test_unique_values_for_lsh_returns_most_frequent(admin_engine):
schema = introspect(admin_engine, "testdb", "dw")
# Before classify_all, all text columns are eligible=True by default. Sampling
# only touches text types regardless.
values, skipped, truncated = unique_values_for_lsh(
admin_engine, schema, LshConfig(max_values_per_column=100)
)
# dim_pazienti.citta: Milano, Bergamo, Brescia (3 distinct, all eligible text)
citta = values.get("dim_pazienti", {}).get("citta")
assert citta is not None
assert set(citta) == {"Milano", "Bergamo", "Brescia"}
def test_unique_values_for_lsh_excludes_non_text(admin_engine):
schema = introspect(admin_engine, "testdb", "dw")
values, _, _ = unique_values_for_lsh(
admin_engine, schema, LshConfig(max_values_per_column=100)
)
# id_paziente is bigint — must never appear in the LSH values.
assert "id_paziente" not in values.get("dim_pazienti", {})
def test_unique_values_for_lsh_truncation_reported(admin_engine):
schema = introspect(admin_engine, "testdb", "dw")
# Force a tiny cap so procedura/diagnosi columns (which have >2 distinct values)
# are reported as truncated rather than silently cut.
_, _, truncated = unique_values_for_lsh(
admin_engine, schema, LshConfig(max_values_per_column=1)
)
truncated_cols = {(t.table, t.column) for t in truncated}
# fct_ricoveri has several eligible text columns with distinct values
assert any(t[0] == "fct_ricoveri" for t in truncated_cols)
def test_adapter_sampling_is_distinct_and_frequency_ranked(admin_engine):
values = sample_column(admin_engine, "dw", "fct_ricoveri", "reparto", limit=2)
assert values == ["cardiologia", "pronto soccorso"]
def test_adapter_distinct_values_reports_truncation(admin_engine):
result = distinct_values(
admin_engine, "dw", "fct_ricoveri", "reparto", max_values=1
)
assert result.values == ["cardiologia"]
assert result.truncated is True