write output of long chain test to /dev/null

This avoids generating a large file in the source tree that we don't need. In my
runs in a Linux VM, this also significantly speeds up the test suite.
Closes #1720.

diff --git a/tests/regression_tests/large/test_large_graphs.py b/tests/regression_tests/large/test_large_graphs.py
index 5a94fbb957a697aef7c282588969f8b44acaed0a..b6f69c9b0eb789a302a3c3f9639fb4aca1ce0d6b 100644 (file)
--- a/tests/regression_tests/large/test_large_graphs.py
+++ b/tests/regression_tests/large/test_large_graphs.py
@@ -5,9 +5,6 @@ import os
 import sys\r
 \r
 \r
-TEST_DIR = os.path.dirname(os.path.realpath(__file__))\r
-\r
-\r
 class TestLargeGraphs(TestCase):\r
        @skipIf(sys.platform == 'win32', reason='https://gitlab.com/graphviz/graphviz/-/issues/1710')\r
        def test_long_chain(self):\r
@@ -32,5 +29,5 @@ class TestLargeGraphs(TestCase):
                        graph.render("long_chain")\r
                """\r
                subprocess.check_call([\r
-                       'dot', '-Tsvg', '-O', os.path.join(TEST_DIR, 'long_chain')\r
+                       'dot', '-Tsvg', '-O', os.devnull\r
                ])\r