Return to the original directory after exec'ing a file

If the file that is exec'd chdirs to a directory that doesn't exist
at the end of the execution, then we will fail to connect to the
SQLite database (due to a failing `os.getcwd` command).

We can easily fix this if we ensure we are in a directory that
exists after executing the foreign code. Returning to the original
directory seems to be a sensible choice.

1 files changed, 4 insertions, 0 deletions

diff --git a/coverage/execfile.py b/coverage/execfile.py
index fbd0228c..4edbc8ac 100644
--- a/coverage/execfile.py
+++ b/coverage/execfile.py
@@ -193,7 +193,11 @@ class PyRunner(object):
 
         # Execute the code object.
         try:
+            # Return to the original directory in case the test code exits in
+            # a non-existent directory.
+            cwd = os.getcwd()
             exec(code, main_mod.__dict__)
+            os.chdir(cwd)
         except SystemExit:                          # pylint: disable=try-except-raise
             # The user called sys.exit().  Just pass it along to the upper
             # layers, where it will be handled.