Unset the DISPLAY environment variable in tools test

This ensures that the test fails instead of hanging if print usage and
exit fails and the program continues and tries to open the display.

diff --git a/rtest/test_tools.py b/rtest/test_tools.py
index e4beca204c38c80ee00d1e115ac447716ed96027..dafbcf4f931129019df4126d7b1ab2978abb6a6f 100644 (file)
--- a/rtest/test_tools.py
+++ b/rtest/test_tools.py
@@ -141,9 +141,14 @@ def test_tools(tool):
             pytest.skip('gvpack does not find libgvplugin_neato_layout.so.6'
                         'when built with CMake (#1838)')
 
+    # Ensure that X fails to open display
+    environ_copy = os.environ.copy()
+    environ_copy.pop('DISPLAY', None)
+
     # Test usage
     output = subprocess.check_output(
         [tool, '-?'],
+        env=environ_copy,
         stdin=subprocess.DEVNULL,
         stderr=subprocess.STDOUT,
         universal_newlines=True,