Simplify and optimize FindCycles

test/errors/gyptest-errors.py

Index: test/errors/gyptest-errors.py
diff --git a/test/errors/gyptest-errors.py b/test/errors/gyptest-errors.py
index 5f66bac0228e5ea6a44615dd3412a791c09d1d7f..4612c16b95d389cc2cda7be0b2ff13916a64caac 100755
--- a/test/errors/gyptest-errors.py
+++ b/test/errors/gyptest-errors.py
@@ -39,6 +39,14 @@ stderr = ("gyp: Key 'targets' repeated at level 1 with key path '' while "
 test.run_gyp('duplicate_node.gyp', '--check', status=1, stderr=stderr,
              match=TestCmd.match_re_dotall)
 
+stderr = (".*target0.*target1.*target2.*target0.*")
+test.run_gyp('dependency_cycle.gyp', status=1, stderr=stderr,
+             match=TestCmd.match_re_dotall)
+
+stderr = (".*file_cycle0.*file_cycle1.*file_cycle0.*")
+test.run_gyp('file_cycle0.gyp', status=1, stderr=stderr,
+             match=TestCmd.match_re_dotall)
+
 stderr = 'gyp: Duplicate basenames in sources section, see list above\n'
 test.run_gyp('duplicate_basenames.gyp', status=1, stderr=stderr)