add unit test_providers

tests/unit/test_providers.py

@@ -0,0 +1,28 @@
+import pytest
+from unittest import mock
+
+from dbt.context.providers import BaseResolver
+
+
+class TestBaseResolver:
+    class ResolverSubclass(BaseResolver):
+        def __call__(self, *args: str):
+            pass
+
+    @pytest.fixture
+    def resolver(self):
+        return self.ResolverSubclass(
+            db_wrapper=mock.Mock(),
+            model=mock.Mock(),
+            config=mock.Mock(),
+            manifest=mock.Mock(),
+        )
+
+    @pytest.mark.parametrize(
+        "empty,expected_resolve_limit",
+        [(False, None), (True, 0)],
+    )
+    def test_resolve_limit(self, resolver, empty, expected_resolve_limit):
+        resolver.config.args.EMPTY = empty
+
+        assert resolver.resolve_limit == expected_resolve_limit

tests/unit/test_relation.py

@@ -65,3 +65,4 @@ def test_render_limited(limit, expected_result):
     )
     actual_result = my_relation.render_limited()
     assert actual_result == expected_result
+    assert str(my_relation) == expected_result