diff -r 3180ff7f6025 -r d4805a5e7e70 tests/test-status-color.t
--- a/tests/test-status-color.t	Sun Nov 26 11:22:27 2017 +0900
+++ b/tests/test-status-color.t	Tue Nov 28 13:27:43 2017 -0500
@@ -29,6 +29,22 @@
   [status.unknown|? ][status.unknown|b/2/in_b_2]
   [status.unknown|? ][status.unknown|b/in_b]
   [status.unknown|? ][status.unknown|in_root]
+HGPLAIN disables color
+  $ HGPLAIN=1 hg status --color=debug
+  ? a/1/in_a_1
+  ? a/in_a
+  ? b/1/in_b_1
+  ? b/2/in_b_2
+  ? b/in_b
+  ? in_root
+HGPLAINEXCEPT=color does not disable color
+  $ HGPLAINEXCEPT=color hg status --color=debug
+  [status.unknown|? ][status.unknown|a/1/in_a_1]
+  [status.unknown|? ][status.unknown|a/in_a]
+  [status.unknown|? ][status.unknown|b/1/in_b_1]
+  [status.unknown|? ][status.unknown|b/2/in_b_2]
+  [status.unknown|? ][status.unknown|b/in_b]
+  [status.unknown|? ][status.unknown|in_root]
 
 hg status with template
   $ hg status -T "{label('red', path)}\n" --color=debug