--- a/tests/test-diff-color.t	Mon May 01 16:43:43 2017 +0200
+++ b/tests/test-diff-color.t	Tue May 02 20:01:54 2017 +0200
@@ -3,6 +3,7 @@
   $ cat <<EOF >> $HGRCPATH
   > [ui]
   > color = always
+  > formatted = always
   > [color]
   > mode = ansi
   > EOF
@@ -49,6 +50,38 @@
    a
    c
 
+(check that 'ui.color=yes' match '--color=auto')
+
+  $ hg diff --nodates --config ui.formatted=no
+  diff -r cf9f4ba66af2 a
+  --- a/a
+  +++ b/a
+  @@ -2,7 +2,7 @@
+   c
+   a
+   a
+  -b
+  +dd
+   a
+   a
+   c
+
+(check that 'ui.color=no' disable color)
+
+  $ hg diff --nodates --config ui.formatted=yes --config ui.color=no
+  diff -r cf9f4ba66af2 a
+  --- a/a
+  +++ b/a
+  @@ -2,7 +2,7 @@
+   c
+   a
+   a
+  -b
+  +dd
+   a
+   a
+   c
+
 --unified=2
 
   $ hg diff --nodates -U 2