patch 8.0.0616: not always setting 'background' correctly after :hi Normal
Problem: When setting the cterm background with ":hi Normal" the value of
'background' may be set wrongly.
Solution: Check that the color is less than 16. Don't set 'background' when
it was set explicitly. (Lemonboy, closes #1710)
diff --git a/src/testdir/test_syntax.vim b/src/testdir/test_syntax.vim
index 8d4be00..eb093c8 100644
--- a/src/testdir/test_syntax.vim
+++ b/src/testdir/test_syntax.vim
@@ -401,3 +401,26 @@
call assert_fails('hi XXX xxx=White', 'E423:')
endfunc
+func Test_bg_detection()
+ if has('gui_running')
+ return
+ endif
+ " auto-detection of &bg, make sure sure it isn't set anywhere before
+ " this test
+ hi Normal ctermbg=0
+ call assert_equal('dark', &bg)
+ hi Normal ctermbg=4
+ call assert_equal('dark', &bg)
+ hi Normal ctermbg=12
+ call assert_equal('light', &bg)
+ hi Normal ctermbg=15
+ call assert_equal('light', &bg)
+
+ " manually-set &bg takes precendence over auto-detection
+ set bg=light
+ hi Normal ctermbg=4
+ call assert_equal('light', &bg)
+ set bg=dark
+ hi Normal ctermbg=12
+ call assert_equal('dark', &bg)
+endfunc