Tests/dssm second fit refits (#166)

- Added "second fit refits" test for DSSM

Author: feldlime

tests/models/test_dssm.py

@@ -25,6 +25,7 @@
 from rectools.models import DSSMModel
 from rectools.models.dssm import DSSM
 from rectools.models.vector import ImplicitRanker
+from tests.models.utils import assert_second_fit_refits_model
 
 from .data import INTERACTIONS
 
@@ -33,6 +34,9 @@
 @pytest.mark.filterwarnings("ignore::UserWarning")
 class TestDSSMModel:
     def setup_method(self) -> None:
+        self._seed_everything()
+
+    def _seed_everything(self) -> None:
         seed_everything(42, workers=True)
 
     @pytest.fixture
@@ -330,3 +334,7 @@ def test_raises_when_no_features_in_dataset(self, dataset: Dataset, exclude_feat
         model = DSSMModel()
         with pytest.raises(ValueError, match="requires user and item features"):
             model.fit(dataset)
+
+    def test_second_fit_refits_model(self, dataset: Dataset) -> None:
+        model = DSSMModel(deterministic=True)
+        assert_second_fit_refits_model(model, dataset, pre_fit_callback=self._seed_everything)

tests/models/utils.py

@@ -12,6 +12,7 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
+import typing as tp
 from copy import deepcopy
 
 import pandas as pd
@@ -20,9 +21,23 @@
 from rectools.models.base import ModelBase
 
 
-def assert_second_fit_refits_model(model: ModelBase, dataset: Dataset) -> None:
+def _dummy_func() -> None:
+    pass
+
+
+def assert_second_fit_refits_model(
+    model: ModelBase, dataset: Dataset, pre_fit_callback: tp.Optional[tp.Callable[[], None]] = None
+) -> None:
+    pre_fit_callback = pre_fit_callback or _dummy_func
+
+    pre_fit_callback()
     model_1 = deepcopy(model).fit(dataset)
-    model_2 = deepcopy(model).fit(dataset).fit(dataset)
+
+    pre_fit_callback()
+    model_2 = deepcopy(model).fit(dataset)
+    pre_fit_callback()
+    model_2.fit(dataset)
+
     k = dataset.item_id_map.external_ids.size
 
     reco_u2i_1 = model_1.recommend(dataset.user_id_map.external_ids, dataset, k, False)