Add tests of bug #806, and ensure it's fixed even if the program ends with an exception

4 files changed, 40 insertions, 4 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 4fb6e112..52ec0761 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -41,6 +41,9 @@ Unreleased
   be reported as warnings.  As with other warnings, you can suppress them with
   the ``[run] disable_warnings`` configuration setting.
 
+- Coverage.py no longer fails if the user program deletes its current
+  directory, closing `issue 806`_.  Thanks, Dan Hemberger.
+
 - The scrollbar markers in the HTML report now accurately show the highlighted
   lines, regardless of what categories of line are highlighted.
 
@@ -50,6 +53,7 @@ Unreleased
 - The deprecated `Reporter.file_reporters` property has been removed.
 
 .. _ShiningPanda: https://wiki.jenkins.io/display/JENKINS/ShiningPanda+Plugin
+.. _issue 806: https://github.com/nedbat/coveragepy/pull/806
 
 
 .. _changes_50a5:
diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
index 972e818b..06eef4f7 100644
--- a/CONTRIBUTORS.txt
+++ b/CONTRIBUTORS.txt
@@ -33,6 +33,7 @@ Christine Lytwynec
 Christoph Zwerschke
 Conrad Ho
 Cosimo Lupo
+Dan Hemberger
 Dan Riti
 Dan Wandschneider
 Danek Duvall
diff --git a/coverage/execfile.py b/coverage/execfile.py
index 4edbc8ac..972d8f1b 100644
--- a/coverage/execfile.py
+++ b/coverage/execfile.py
@@ -192,12 +192,11 @@ class PyRunner(object):
             raise CoverageException(msg.format(filename=self.arg0, exc=exc))
 
         # Execute the code object.
+        # Return to the original directory in case the test code exits in
+        # a non-existent directory.
+        cwd = os.getcwd()
         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.
@@ -236,6 +235,8 @@ class PyRunner(object):
                 raise ExceptionDuringRun(typ, err, tb.tb_next)
             else:
                 sys.exit(1)
+        finally:
+            os.chdir(cwd)
 
 
 def run_python_module(args):
diff --git a/tests/test_process.py b/tests/test_process.py
index 0979cc2c..a5303338 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -1293,6 +1293,36 @@ class UnicodeFilePathsTest(CoverageTest):
         self.assertEqual(out, report_expected)
 
 
+class YankedDirectoryTest(CoverageTest):
+    """Tests of what happens when the current directory is deleted."""
+
+    BUG_806 = """\
+        import os
+        import sys
+        import tempfile
+
+        tmpdir = tempfile.mkdtemp()
+        os.chdir(tmpdir)
+        os.rmdir(tmpdir)
+        print(sys.argv[1])
+        """
+
+    def test_removing_directory(self):
+        self.make_file("bug806.py", self.BUG_806)
+        out = self.run_command("coverage run bug806.py noerror")
+        self.assertEqual(out, "noerror\n")
+
+    def test_removing_directory_with_error(self):
+        self.make_file("bug806.py", self.BUG_806)
+        out = self.run_command("coverage run bug806.py")
+        self.assertEqual(out, textwrap.dedent("""\
+            Traceback (most recent call last):
+              File "bug806.py", line 8, in <module>
+                print(sys.argv[1])
+            IndexError: list index out of range
+            """))
+
+
 def possible_pth_dirs():
     """Produce a sequence of directories for trying to write .pth files."""
     # First look through sys.path, and if we find a .pth file, then it's a good