test: make metacov work with xdist

I was using pytest.__file__ as a directory, but in 5.3.2, pytest changed
to be a package, so that wasn't the site-packages directory anymore, and
our .pth file was written someplace useless.

Now we don't rely on the structure of pytest (why did we ever?), and it
works again.

1 files changed, 2 insertions, 1 deletions

diff --git a/igor.py b/igor.py
index 0ea93e40..58774036 100644
--- a/igor.py
+++ b/igor.py
@@ -15,6 +15,7 @@ import inspect
 import os
 import platform
 import sys
+import sysconfig
 import textwrap
 import warnings
 import zipfile
@@ -143,7 +144,7 @@ def run_tests_with_coverage(tracer, *runner_args):
     # The .pth file seems to have to be alphabetically after easy-install.pth
     # or the sys.path entries aren't created right?
     # There's an entry in "make clean" to get rid of this file.
-    pth_dir = os.path.dirname(pytest.__file__)
+    pth_dir = sysconfig.get_path("purelib")
     pth_path = os.path.join(pth_dir, "zzz_metacov.pth")
     with open(pth_path, "w") as pth_file:
         pth_file.write("import coverage; coverage.process_startup()\n")