test: Use pytest-snapshot for error tests (#554)

pyproject.toml

@@ -37,6 +37,7 @@ dev-dependencies = [
     "pytest >=8.3.2,<9",
     "pytest-cov >=5.0.0,<6",
     "pytest-notebook >=0.10.0,<0.11",
+    "pytest-snapshot >=0.9.0,<1",
     "mypy ==1.10.0",
     "pre-commit >=3.6.0,<4",
     "ruff >=0.6.2,<0.7",

tests/error/test_array_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_array_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_array_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_comprehension_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_comprehension_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_comprehension_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_errors_on_usage.py

@@ -18,5 +18,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_errors_on_usage(file, capsys):
-    run_error_test(file, capsys)
+def test_errors_on_usage(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_experimental_errors.py

@@ -16,6 +16,6 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_experimental_errors(file, capsys):
+def test_experimental_errors(file, capsys, snapshot):
     with disable_experimental_features():
-        run_error_test(file, capsys)
+        run_error_test(file, capsys, snapshot)

tests/error/test_inout_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_inout_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_inout_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_iter_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_iter_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_iter_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_linear_errors.py

@@ -18,5 +18,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_linear_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_linear_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_misc_errors.py

@@ -20,8 +20,8 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_misc_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_misc_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)
 
 
 def test_extern_bad_type_syntax():

tests/error/test_nested_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_nested_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_nested_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_poly_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_type_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_type_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_py_errors.py

@@ -23,13 +23,13 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_py_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_py_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)
 
 
 @pytest.mark.skipif(tket2_installed, reason="tket2 is installed")
-def test_tket2_not_installed(capsys):
+def test_tket2_not_installed(capsys, snapshot):
     path = (
         pathlib.Path(__file__).parent.resolve() / "py_errors" / "tket2_not_installed.py"
     )
-    run_error_test(str(path), capsys)
+    run_error_test(str(path), capsys, snapshot)

tests/error/test_struct_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_struct_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_struct_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_tensor_errors.py

@@ -15,5 +15,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_type_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_type_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/test_type_errors.py

@@ -18,5 +18,5 @@
 
 
 @pytest.mark.parametrize("file", files)
-def test_type_errors(file, capsys):
-    run_error_test(file, capsys)
+def test_type_errors(file, capsys, snapshot):
+    run_error_test(file, capsys, snapshot)

tests/error/util.py

@@ -10,19 +10,17 @@
 import guppylang.decorator as decorator
 
 
-def run_error_test(file, capsys):
+def run_error_test(file, capsys, snapshot):
     file = pathlib.Path(file)
 
     with pytest.raises(GuppyError):
         importlib.import_module(f"tests.error.{file.parent.name}.{file.name}")
 
     err = capsys.readouterr().err
+    err = err.replace(str(file), "$FILE")
 
-    with pathlib.Path(file.with_suffix(".err")).open() as f:
-        exp_err = f.read()
-
-    exp_err = exp_err.replace("$FILE", str(file))
-    assert err == exp_err
+    snapshot.snapshot_dir = str(file.parent)
+    snapshot.assert_match(err, file.with_suffix(".err").name)
 
 
 util = GuppyModule("test")