diff --git a/conftest.py b/conftest.py
index 4ca6c82a..60af4158 100644
--- a/conftest.py
+++ b/conftest.py
@@ -94,7 +94,7 @@ def environment(request):
     if int(version) == py_version:
         return get_default_environment()
 
-    return get_system_environment('python%s.%s' % tuple(version))
+    return get_system_environment(version[0] + '.' + version[1:])
 
 
 @pytest.fixture(scope='session')
diff --git a/test/run.py b/test/run.py
index 6d0b2926..0e6da5a4 100755
--- a/test/run.py
+++ b/test/run.py
@@ -435,7 +435,7 @@ if __name__ == '__main__':
             return 1
 
     if arguments['--env']:
-        environment = get_system_environment('python' + arguments['--env'])
+        environment = get_system_environment(arguments['--env'])
     else:
         # Will be 3.6.
         environment = get_default_environment()