tests: Automatically run from source-tree root; and use default temp dir (#3426)

gnprice · web-flow · commit 45a5cf32eee9 · 2017-05-23T14:11:01.000-07:00
Several bits of our test runner system assume that the current working directory when tests are run is the root of the mypy source tree. This is a fine constraint to require, but the way we fail if that constraint is broken is an error in each test case's setup, which pytest presents as one of those massive stack traces it specializes in. See #3412. These dependencies include the way we find a temporary directory to use, and something to do with some imports. For the tempdir, just use `tempfile` in the usual default way -- as a bonus, we no longer need to stick temporary files under the source tree. The import issues seem like bugs, but rather than chase down that kind of bug in the test harness, just take care of the working directory automatically.
diff --git a/conftest.py b/conftest.py
@@ -1,3 +1,12 @@
+import os.path
+
+import pytest
+
 pytest_plugins = [
     'mypy.test.data',
 ]
+
+def pytest_configure(config):
+    mypy_source_root = os.path.dirname(os.path.abspath(__file__))
+    if os.getcwd() != mypy_source_root:
+        os.chdir(mypy_source_root)
diff --git a/mypy/myunit/__init__.py b/mypy/myunit/__init__.py
@@ -120,8 +120,7 @@ def run(self) -> None:
 
     def set_up(self) -> None:
         self.old_cwd = os.getcwd()
-        self.tmpdir = tempfile.TemporaryDirectory(prefix='mypy-test-',
-                dir=os.path.abspath('tmp-test-dirs'))
+        self.tmpdir = tempfile.TemporaryDirectory(prefix='mypy-test-')
         os.chdir(self.tmpdir.name)
         os.mkdir('tmp')
         if self.suite:
