add context manager to temporarily change the cwd (#2377)

[etc/vim.git] / tests / util.py

diff --git a/tests/util.py b/tests/util.py
index 9c3d3cbc99d031e2a1d6cc556bd0b4ca0af878c0..e83017f5ad3eba54a98ab78bf560f7e46318dc2d 100644 (file)
--- a/tests/util.py
+++ b/tests/util.py
@@ -1,7 +1,13 @@
+import os
 import unittest
-from contextlib import contextmanager
 from pathlib import Path
-from typing import List, Tuple, Iterator
+from typing import Iterator, List, Tuple, Any
+from contextlib import contextmanager
+from functools import partial
+
+import black
+from black.output import out, err
+from black.debug import DebugVisitor
 
 THIS_DIR = Path(__file__).parent
 PROJECT_ROOT = THIS_DIR.parent
@@ -9,26 +15,52 @@ EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"
 DETERMINISTIC_HEADER = "[Deterministic header]"
 
 
-@contextmanager
-def skip_if_exception(e: str) -> Iterator[None]:
-    try:
-        yield
-    except Exception as exc:
-        if exc.__class__.__name__ == e:
-            unittest.skip(f"Encountered expected exception {exc}, skipping")
-        else:
-            raise
+DEFAULT_MODE = black.Mode()
+ff = partial(black.format_file_in_place, mode=DEFAULT_MODE, fast=True)
+fs = partial(black.format_str, mode=DEFAULT_MODE)
+
+
+def dump_to_stderr(*output: str) -> str:
+    return "\n" + "\n".join(output) + "\n"
+
+
+class BlackBaseTestCase(unittest.TestCase):
+    maxDiff = None
+    _diffThreshold = 2 ** 20
+
+    def assertFormatEqual(self, expected: str, actual: str) -> None:
+        if actual != expected and not os.environ.get("SKIP_AST_PRINT"):
+            bdv: DebugVisitor[Any]
+            out("Expected tree:", fg="green")
+            try:
+                exp_node = black.lib2to3_parse(expected)
+                bdv = DebugVisitor()
+                list(bdv.visit(exp_node))
+            except Exception as ve:
+                err(str(ve))
+            out("Actual tree:", fg="red")
+            try:
+                exp_node = black.lib2to3_parse(actual)
+                bdv = DebugVisitor()
+                list(bdv.visit(exp_node))
+            except Exception as ve:
+                err(str(ve))
+        self.assertMultiLineEqual(expected, actual)
 
 
 def read_data(name: str, data: bool = True) -> Tuple[str, str]:
     """read_data('test_name') -> 'input', 'output'"""
     if not name.endswith((".py", ".pyi", ".out", ".diff")):
         name += ".py"
-    _input: List[str] = []
-    _output: List[str] = []
     base_dir = THIS_DIR / "data" if data else PROJECT_ROOT
-    with open(base_dir / name, "r", encoding="utf8") as test:
+    return read_data_from_file(base_dir / name)
+
+
+def read_data_from_file(file_name: Path) -> Tuple[str, str]:
+    with open(file_name, "r", encoding="utf8") as test:
         lines = test.readlines()
+    _input: List[str] = []
+    _output: List[str] = []
     result = _input
     for line in lines:
         line = line.replace(EMPTY_LINE, "")
@@ -41,3 +73,14 @@ def read_data(name: str, data: bool = True) -> Tuple[str, str]:
         # If there's no output marker, treat the entire file as already pre-formatted.
         _output = _input[:]
     return "".join(_input).strip() + "\n", "".join(_output).strip() + "\n"
+
+
+@contextmanager
+def change_directory(path: Path) -> Iterator[None]:
+    """Context manager to temporarily chdir to a different directory."""
+    previous_dir = os.getcwd()
+    try:
+        os.chdir(path)
+        yield
+    finally:
+        os.chdir(previous_dir)