fix(core): preserve adapter command contracts

harness/tests/test_dwh_adapters.py

@@ -85,14 +85,17 @@ def test_postgres_sampling_delegates_to_paired_sampling_functions(monkeypatch):
         )
         or ["A", "B"],
     )
+    distinct_calls = []
     monkeypatch.setattr(
         "tht.adapters.dwh.postgres.sampling.distinct_values",
-        lambda engine, schema, table, column: expected,
+        lambda engine, schema, table, column, *, max_values: distinct_calls.append(max_values)
+        or expected,
     )
 
     assert adapter.sample_column("sales", "region", limit=2) == ["A", "B"]
     assert calls == [(adapter._engine, "dw", "sales", "region", 2)]
-    assert adapter.distinct_values("sales", "region") is expected
+    assert adapter.distinct_values("sales", "region", limit=17) is expected
+    assert distinct_calls == [17]
 
 
 def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
@@ -104,10 +107,10 @@ def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
     )
     monkeypatch.setattr(
         "tht.adapters.dwh.thoth_rest.sampling.distinct_values_rest",
-        lambda client, schema, table, column: expected,
+        lambda client, schema, table, column, *, max_values: expected,
     )
     assert adapter.sample_column("sales", "region", limit=2) == ["A", "B"]
-    assert adapter.distinct_values("sales", "region") is expected
+    assert adapter.distinct_values("sales", "region", limit=17) is expected
 
     def fail(*args, **kwargs):
         raise RestError("transport failed")
@@ -117,7 +120,7 @@ def test_rest_sampling_delegates_and_translates_transport_errors(monkeypatch):
     with pytest.raises(ExecutionError, match="transport failed"):
         adapter.sample_column("sales", "region", limit=2)
     with pytest.raises(ExecutionError, match="transport failed"):
-        adapter.distinct_values("sales", "region")
+        adapter.distinct_values("sales", "region", limit=17)
 
 
 def test_rest_distinct_values_reports_transport_truncation():