Extend toggling test to also verify the updated campaign metadata

tests/test_campaign.py

@@ -5,7 +5,7 @@
 from pandas.testing import assert_frame_equal
 from pytest import param
 
-from baybe.campaign import Campaign
+from baybe.campaign import _EXCLUDED, Campaign
 from baybe.parameters.numerical import NumericalDiscreteParameter
 from baybe.searchspace.discrete import SubspaceDiscrete
 
@@ -51,16 +51,33 @@ def test_get_surrogate(campaign, n_iterations, batch_size):
     ],
     ids=["regular", "anti"],
 )
-def test_candidate_filter(anti, expected):
-    """The candidate filter extracts the correct subset of points."""
+@pytest.mark.parametrize("exclude", [True, False], ids=["exclude", "include"])
+def test_candidate_filter(exclude, anti, expected):
+    """The candidate filter extracts the correct subset of points and the campaign
+    metadata is updated accordingly."""  # noqa
+
     subspace = SubspaceDiscrete.from_product(
         [
             NumericalDiscreteParameter("a", [0, 1]),
             NumericalDiscreteParameter("b", [3, 4, 5]),
         ]
     )
     campaign = Campaign(subspace)
-    df = campaign.toggle_discrete_candidates(pd.DataFrame({"a": [0]}), False, anti=anti)
-    assert_frame_equal(
-        df, pd.merge(df.reset_index(), expected).set_index("index"), check_names=False
+
+    # Set metadata to opposite of targeted value so that we can verify the effect later
+    campaign._searchspace_metadata[_EXCLUDED] = not exclude
+
+    # Toggle the candidates
+    df = campaign.toggle_discrete_candidates(
+        pd.DataFrame({"a": [0]}), exclude, anti=anti
     )
+
+    # Assert that the filtering is correct
+    rows = pd.merge(df.reset_index(), expected).set_index("index")
+    assert_frame_equal(df, rows, check_names=False)
+
+    # Assert that metadata is set correctly
+    target = campaign._searchspace_metadata.loc[rows.index, _EXCLUDED]
+    other = campaign._searchspace_metadata[_EXCLUDED].drop(index=rows.index)
+    assert all(target == exclude)  # must contain the updated values
+    assert all(other != exclude)  # must contain the original values