fix(dwh): validate adapter limits strictly

harness/tests/l0/test_db_sampling.py

@@ -11,6 +11,22 @@ from tht.db.sampling import distinct_values, is_text_type, sample_column, unique
 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)")

harness/tests/test_dwh_adapters.py

@@ -2,6 +2,7 @@ import pytest
 from sqlalchemy.exc import OperationalError
 
 from tht.config import DatabaseConfig, RestConfig
+from tht.db.sampling import distinct_values_rest, sample_column_rest
 from tht.execute import ExecutionError
 from tht.ports import DistinctValues, DwhAdapter
 from tht.rest.client import RestError
@@ -45,12 +46,31 @@ def test_adapter_satisfies_dwh_protocol(factory):
 
 
 @pytest.mark.parametrize("factory", [postgres_factory, rest_factory])
-def test_run_query_requires_explicit_positive_limit(factory):
+@pytest.mark.parametrize("invalid_limit", [True, 1.5, 0, -1])
+def test_run_query_rejects_non_positive_integer_limit(factory, invalid_limit):
     adapter = factory()
+    with pytest.raises(ValueError, match="positive integer"):
+        adapter.run_query("select 1", limit=invalid_limit)
+
+
+@pytest.mark.parametrize("factory", [postgres_factory, rest_factory])
+def test_run_query_requires_explicit_limit(factory):
     with pytest.raises(TypeError):
-        adapter.run_query("select 1")
-    with pytest.raises(ValueError, match="positive"):
-        adapter.run_query("select 1", limit=0)
+        factory().run_query("select 1")
+
+
+@pytest.mark.parametrize("invalid_limit", [True, 1.5, 0, -1])
+def test_rest_sampling_rejects_non_positive_integer_limit(invalid_limit):
+    class Client:
+        def top_values(self, *args):
+            raise AssertionError("transport must not be used")
+
+    with pytest.raises(ValueError, match="positive integer"):
+        sample_column_rest(Client(), "dw", "sales", "region", limit=invalid_limit)
+    with pytest.raises(ValueError, match="positive integer"):
+        distinct_values_rest(
+            Client(), "dw", "sales", "region", max_values=invalid_limit
+        )
 
 
 def test_postgres_sampling_delegates_to_paired_sampling_functions(monkeypatch):
@@ -101,8 +121,6 @@ def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
 
 
 def test_rest_distinct_values_reports_transport_truncation():
-    from tht.db.sampling import distinct_values_rest
-
     class Client:
         def top_values(self, schema, table, column, limit):
             assert (schema, table, column, limit) == ("dw", "sales", "region", 3)