Strengthen pairwise ranking regression assertions

tests/test_ranking_refinements.py

@@ -115,9 +115,17 @@ def test_pairwise_harness_rankings_exclude_low_data_harnesses(tmp_path):
     harness_df, model_df, pair_df = rankings.load_and_rank(csv_path)
 
     assert set(harness_df["Category"]) == {"Claude Code", "OpenCode"}
-    assert not pair_df["Category"].str.contains("Codex|Qwen Code").any()
+    assert set(pair_df["Category"]) == {
+        "m1 + Claude Code",
+        "m1 + OpenCode",
+        "m2 + Claude Code",
+        "m2 + OpenCode",
+    }
     assert set(model_df["Category"]) == {"m1", "m2"}
 
+    model_by_category = model_df.set_index("Category")
+    assert model_by_category.loc["m1", "Bench A"] == pytest.approx(0.838)
+
 
 def test_ranking_minimum_height_is_reduced_without_changing_matrix_minimum():
     source = Path("src/charts.py").read_text()