1 files changed, 43 insertions, 0 deletions
diff --git a/tests/test_surface.py b/tests/test_surface.py
new file mode 100644
index 0000000..78c4d5e
--- /dev/null
+++ b/tests/test_surface.py
@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+import pytest
+
+from gap_pipeline.surface import (
+    apply_rename_map,
+    create_surface_variant,
+    validate_rename_map,
+)
+
+
+def test_math_only_rename_preserves_english_article(item) -> None:
+    text = r"Let \(a\) be a randomly chosen value with \(a>0\)."
+    renamed = apply_rename_map(text, {"a": "coefalpha"})
+    assert renamed == (
+        r"Let \(coefalpha\) be a randomly chosen value with \(coefalpha>0\)."
+    )
+
+
+def test_surface_variant_changes_problem_and_solution(item) -> None:
+    variant = create_surface_variant(
+        item,
+        "descriptive_long",
+        {"a": "positiveScalar"},
+    )
+    assert "positiveScalar" in variant.problem
+    assert "positiveScalar" in variant.solution
+    assert "Let positiveScalar" not in variant.problem
+
+
+def test_collision_and_nonbijection_are_rejected(item) -> None:
+    with pytest.raises(ValueError, match="collides"):
+        validate_rename_map(
+            {"a": "a"},
+            existing_identifiers=["a"],
+            scientific_constants=[],
+        )
+    with pytest.raises(ValueError, match="one-to-one"):
+        validate_rename_map(
+            {"a": "sharedName", "b": "sharedName"},
+            existing_identifiers=["a", "b"],
+            scientific_constants=[],
+        )