test: add canonical party set validation for SVD flip direction

tests/test_svd_labels.py

@@ -1,6 +1,79 @@
 """Tests for analysis/svd_labels module."""
 
 
+def test_canonical_party_sets_contain_expected_parties():
+    """Verify CANONICAL_RIGHT and CANONICAL_LEFT contain the expected parties."""
+    from analysis.config import CANONICAL_LEFT, CANONICAL_RIGHT
+
+    assert "PVV" in CANONICAL_RIGHT
+    assert "FVD" in CANONICAL_RIGHT
+    assert "JA21" in CANONICAL_RIGHT
+    assert "SGP" in CANONICAL_RIGHT
+
+    assert "SP" in CANONICAL_LEFT
+    assert "PvdA" in CANONICAL_LEFT
+    assert "PvdD" in CANONICAL_LEFT
+    assert "DENK" in CANONICAL_LEFT
+    assert "Volt" in CANONICAL_LEFT
+
+
+def test_compute_flip_direction_uses_all_canonical_right_parties():
+    """Test that flip computation correctly uses all four canonical right parties."""
+    from analysis.config import CANONICAL_LEFT, CANONICAL_RIGHT
+    from analysis.svd_labels import compute_flip_direction
+
+    # Build party scores where ALL canonical right parties are on the left (negative)
+    # and ALL canonical left parties are on the right (positive)
+    party_scores = {}
+    for party in CANONICAL_RIGHT:
+        party_scores[party] = [-0.5]
+    for party in CANONICAL_LEFT:
+        party_scores[party] = [0.5]
+
+    # All right parties on left → should flip
+    assert compute_flip_direction(1, party_scores) is True
+
+    # Invert: all right parties on right (positive), left parties on left (negative)
+    party_scores_inverted = {}
+    for party in CANONICAL_RIGHT:
+        party_scores_inverted[party] = [0.5]
+    for party in CANONICAL_LEFT:
+        party_scores_inverted[party] = [-0.5]
+
+    # All right parties on right → should not flip
+    assert compute_flip_direction(1, party_scores_inverted) is False
+
+
+def test_compute_flip_direction_all_components_canonical_parties():
+    """Test flip for all 10 components using full canonical party sets."""
+    from analysis.config import CANONICAL_LEFT, CANONICAL_RIGHT
+    from analysis.svd_labels import compute_flip_direction
+
+    # Right parties on left (negative), left parties on right (positive)
+    party_scores = {}
+    for party in CANONICAL_RIGHT:
+        party_scores[party] = [-0.7] * 10
+    for party in CANONICAL_LEFT:
+        party_scores[party] = [0.3] * 10
+
+    for comp in range(1, 11):
+        flip = compute_flip_direction(comp, party_scores)
+        assert flip is True, f"Component {comp} should flip (right parties on left)"
+
+    # Inverted: right on right, left on left
+    party_scores_inverted = {}
+    for party in CANONICAL_RIGHT:
+        party_scores_inverted[party] = [0.7] * 10
+    for party in CANONICAL_LEFT:
+        party_scores_inverted[party] = [-0.3] * 10
+
+    for comp in range(1, 11):
+        flip = compute_flip_direction(comp, party_scores_inverted)
+        assert flip is False, (
+            f"Component {comp} should not flip (right parties on right)"
+        )
+
+
 def test_get_svd_label_returns_correct_label():
     """Test that get_svd_label returns the correct label for each component."""
     from analysis.svd_labels import get_svd_label