cpython/Lib/test/support/ast_helper.py
Lysandros Nikolaou 60202609a2
gh-132661: Implement PEP 750 (#132662)
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Co-authored-by: Wingy <git@wingysam.xyz>
Co-authored-by: Koudai Aono <koxudaxi@gmail.com>
Co-authored-by: Dave Peck <davepeck@gmail.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
Co-authored-by: Paul Everitt <pauleveritt@me.com>
Co-authored-by: sobolevn <mail@sobolevn.me>
2025-04-30 11:46:41 +02:00

46 lines
2 KiB
Python

import ast
class ASTTestMixin:
"""Test mixing to have basic assertions for AST nodes."""
def assertASTEqual(self, ast1, ast2):
# Ensure the comparisons start at an AST node
self.assertIsInstance(ast1, ast.AST)
self.assertIsInstance(ast2, ast.AST)
# An AST comparison routine modeled after ast.dump(), but
# instead of string building, it traverses the two trees
# in lock-step.
def traverse_compare(a, b, missing=object()):
if type(a) is not type(b):
self.fail(f"{type(a)!r} is not {type(b)!r}")
if isinstance(a, ast.AST):
for field in a._fields:
if isinstance(a, ast.Constant) and field == "kind":
# Skip the 'kind' field for ast.Constant
continue
value1 = getattr(a, field, missing)
value2 = getattr(b, field, missing)
# Singletons are equal by definition, so further
# testing can be skipped.
if value1 is not value2:
traverse_compare(value1, value2)
elif isinstance(a, list):
try:
for node1, node2 in zip(a, b, strict=True):
traverse_compare(node1, node2)
except ValueError:
# Attempt a "pretty" error ala assertSequenceEqual()
len1 = len(a)
len2 = len(b)
if len1 > len2:
what = "First"
diff = len1 - len2
else:
what = "Second"
diff = len2 - len1
msg = f"{what} list contains {diff} additional elements."
raise self.failureException(msg) from None
elif a != b:
self.fail(f"{a!r} != {b!r}")
traverse_compare(ast1, ast2)