Add check to enforce literal syntax for Python builtin types
This check requires authors to initialize empty or zero builtin types
using the literal syntax (e.g., `{}` instead of `dict()`).
Authors may ignore this requirement for certain builtins using the
`--ignore` option.
Authors may also forbid calling `dict()` with keyword arguments
(`dict(a=1, b=2)`) using the `--no-allow-dict-kwargs` flag.
diff --git a/tests/check_builtin_literals_test.py b/tests/check_builtin_literals_test.py
new file mode 100644
index 0000000..a38e522
--- /dev/null
+++ b/tests/check_builtin_literals_test.py
@@ -0,0 +1,107 @@
+import ast
+
+import pytest
+
+from pre_commit_hooks.check_builtin_literals import BuiltinTypeCall
+from pre_commit_hooks.check_builtin_literals import BuiltinTypeVisitor
+from pre_commit_hooks.check_builtin_literals import main
+from testing.util import get_resource_path
+
+
+@pytest.fixture
+def visitor():
+ return BuiltinTypeVisitor()
+
+
+@pytest.mark.parametrize(
+ ('expression', 'calls'),
+ [
+ # complex
+ ("0j", []),
+ ("complex()", [BuiltinTypeCall('complex', 1, 0)]),
+ ("complex(0, 0)", []),
+ ("complex('0+0j')", []),
+ # float
+ ("0.0", []),
+ ("float()", [BuiltinTypeCall('float', 1, 0)]),
+ ("float('0.0')", []),
+ # int
+ ("0", []),
+ ("int()", [BuiltinTypeCall('int', 1, 0)]),
+ ("int('0')", []),
+ # list
+ ("[]", []),
+ ("list()", [BuiltinTypeCall('list', 1, 0)]),
+ ("list('abc')", []),
+ ("list([c for c in 'abc'])", []),
+ ("list(c for c in 'abc')", []),
+ # str
+ ("''", []),
+ ("str()", [BuiltinTypeCall('str', 1, 0)]),
+ ("str('0')", []),
+ ("[]", []),
+ # tuple
+ ("()", []),
+ ("tuple()", [BuiltinTypeCall('tuple', 1, 0)]),
+ ("tuple('abc')", []),
+ ("tuple([c for c in 'abc'])", []),
+ ("tuple(c for c in 'abc')", []),
+ ],
+)
+def test_non_dict_exprs(visitor, expression, calls):
+ visitor.visit(ast.parse(expression))
+ assert visitor.builtin_type_calls == calls
+
+
+@pytest.mark.parametrize(
+ ('expression', 'calls'),
+ [
+ ("{}", []),
+ ("dict()", [BuiltinTypeCall('dict', 1, 0)]),
+ ("dict(a=1, b=2, c=3)", []),
+ ("dict(**{'a': 1, 'b': 2, 'c': 3})", []),
+ ("dict([(k, v) for k, v in [('a', 1), ('b', 2), ('c', 3)]])", []),
+ ("dict((k, v) for k, v in [('a', 1), ('b', 2), ('c', 3)])", []),
+ ],
+)
+def test_dict_allow_kwargs_exprs(visitor, expression, calls):
+ visitor.visit(ast.parse(expression))
+ assert visitor.builtin_type_calls == calls
+
+
+@pytest.mark.parametrize(
+ ('expression', 'calls'),
+ [
+ ("dict()", [BuiltinTypeCall('dict', 1, 0)]),
+ ("dict(a=1, b=2, c=3)", [BuiltinTypeCall('dict', 1, 0)]),
+ ("dict(**{'a': 1, 'b': 2, 'c': 3})", [BuiltinTypeCall('dict', 1, 0)]),
+ ],
+)
+def test_dict_no_allow_kwargs_exprs(expression, calls):
+ visitor = BuiltinTypeVisitor(allow_dict_kwargs=False)
+ visitor.visit(ast.parse(expression))
+ assert visitor.builtin_type_calls == calls
+
+
+def test_ignore_constructors():
+ visitor = BuiltinTypeVisitor(ignore=('complex', 'dict', 'float', 'int', 'list', 'str', 'tuple'))
+ visitor.visit(ast.parse(open(get_resource_path('builtin_constructors.py'), 'rb').read(), 'builtin_constructors.py'))
+ assert visitor.builtin_type_calls == []
+
+
+def test_failing_file():
+ rc = main([get_resource_path('builtin_constructors.py')])
+ assert rc == 1
+
+
+def test_passing_file():
+ rc = main([get_resource_path('builtin_literals.py')])
+ assert rc == 0
+
+
+def test_failing_file_ignore_all():
+ rc = main([
+ '--ignore=complex,dict,float,int,list,str,tuple',
+ get_resource_path('builtin_constructors.py'),
+ ])
+ assert rc == 0
