diff --git a/_pytest/main.py b/_pytest/main.py
index f1be30601..23775347b 100644
--- a/_pytest/main.py
+++ b/_pytest/main.py
@@ -449,7 +449,7 @@ class Session(FSCollector):
             p = p.dirpath()
         else:
             p = p.new(basename=p.purebasename+".py")
-        return p
+        return str(p)
 
     def _parsearg(self, arg):
         """ return (fspath, names) tuple after checking the file exists. """
diff --git a/pytest.py b/pytest.py
index fe55b153f..197794047 100644
--- a/pytest.py
+++ b/pytest.py
@@ -1,7 +1,7 @@
 """
 unit and functional testing with Python.
 """
-__version__ = '2.0.1.dev9'
+__version__ = '2.0.1.dev10'
 __all__ = ['main']
 
 from _pytest.core import main, UsageError, _preloadplugins
diff --git a/setup.py b/setup.py
index 018a5a308..ad82d081f 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@ def main():
         name='pytest',
         description='py.test: simple powerful testing with Python',
         long_description = long_description,
-        version='2.0.1.dev9',
+        version='2.0.1.dev10',
         url='http://pytest.org',
         license='MIT license',
         platforms=['unix', 'linux', 'osx', 'cygwin', 'win32'],
@@ -67,4 +67,4 @@ def make_entry_points():
     return {'console_scripts': l}
 
 if __name__ == '__main__':
-    main()
+    main()
\ No newline at end of file
diff --git a/testing/acceptance_test.py b/testing/acceptance_test.py
index a53afe7fc..a82f42f4a 100644
--- a/testing/acceptance_test.py
+++ b/testing/acceptance_test.py
@@ -346,6 +346,12 @@ class TestInvocationVariants:
         result.stdout.fnmatch_lines([
             "*2 passed*"
         ])
+        path.join('test_hello.py').remove()
+        result = testdir.runpytest("--pyargs", "tpkg.test_hello")
+        assert result.ret != 0
+        result.stderr.fnmatch_lines([
+            "*file*not*found*test_hello.py",
+        ])
 
     def test_cmdline_python_package_not_exists(self, testdir):
         result = testdir.runpytest("--pyargs", "tpkgwhatv")