patch 8.2.0522: several errors are not tested for
Problem: Several errors are not tested for.
Solution: Add tests. (Yegappan Lakshmanan, closes #5892)
diff --git a/src/testdir/test_preview.vim b/src/testdir/test_preview.vim
index a85798b..628ad2b 100644
--- a/src/testdir/test_preview.vim
+++ b/src/testdir/test_preview.vim
@@ -13,3 +13,50 @@
call assert_equal(wincount, winnr('$'))
bwipe
endfunc
+
+func Test_window_preview()
+ CheckFeature quickfix
+
+ " Open a preview window
+ pedit Xa
+ call assert_equal(2, winnr('$'))
+ call assert_equal(0, &previewwindow)
+
+ " Go to the preview window
+ wincmd P
+ call assert_equal(1, &previewwindow)
+
+ " Close preview window
+ wincmd z
+ call assert_equal(1, winnr('$'))
+ call assert_equal(0, &previewwindow)
+
+ call assert_fails('wincmd P', 'E441:')
+endfunc
+
+func Test_window_preview_from_help()
+ CheckFeature quickfix
+
+ filetype on
+ call writefile(['/* some C code */'], 'Xpreview.c')
+ help
+ pedit Xpreview.c
+ wincmd P
+ call assert_equal(1, &previewwindow)
+ call assert_equal('c', &filetype)
+ wincmd z
+
+ filetype off
+ close
+ call delete('Xpreview.c')
+endfunc
+
+func Test_multiple_preview_windows()
+ new
+ set previewwindow
+ new
+ call assert_fails('set previewwindow', 'E590:')
+ %bw!
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab