patch 8.2.0261: some code not covered by tests

Problem:    Some code not covered by tests.
Solution:   Add test cases. (Yegappan Lakshmanan, closes #5645)

src/testdir/test_cmdline.vim

@@ -632,9 +632,32 @@ func Test_cmdline_search_range()
   1,\&s/b/B/
   call assert_equal('B', getline(2))
 
+  let @/ = 'apple'
+  call assert_fails('\/print', 'E486:')
+
   bwipe!
 endfunc
 
+" Test for the tick mark (') in an excmd range
+func Test_tick_mark_in_range()
+  " If only the tick is passed as a range and no command is specified, there
+  " should not be an error
+  call feedkeys(":'\<CR>", 'xt')
+  call assert_equal("'", getreg(':'))
+  call assert_fails("',print", 'E78:')
+endfunc
+
+" Test for using a line number followed by a search pattern as range
+func Test_lnum_and_pattern_as_range()
+  new
+  call setline(1, ['foo 1', 'foo 2', 'foo 3'])
+  let @" = ''
+  2/foo/yank
+  call assert_equal("foo 3\n", @")
+  call assert_equal(1, line('.'))
+  close!
+endfunc
+
 " Tests for getcmdline(), getcmdpos() and getcmdtype()
 func Check_cmdline(cmdtype)
   call assert_equal('MyCmd a', getcmdline())
@@ -934,4 +957,24 @@ func Test_cmdline_expand_special()
   call assert_fails('e <amatch>', 'E497:')
 endfunc
 
+func Test_cmdwin_jump_to_win()
+  call assert_fails('call feedkeys("q:\<C-W>\<C-W>\<CR>", "xt")', 'E11:')
+  new
+  set modified
+  call assert_fails('call feedkeys("q/:qall\<CR>", "xt")', 'E162:')
+  close!
+  call feedkeys("q/:close\<CR>", "xt")
+  call assert_equal(1, winnr('$'))
+  call feedkeys("q/:exit\<CR>", "xt")
+  call assert_equal(1, winnr('$'))
+endfunc
+
+" Test for backtick expression in the command line
+func Test_cmd_backtick()
+  %argd
+  argadd `=['a', 'b', 'c']`
+  call assert_equal(['a', 'b', 'c'], argv())
+  %argd
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab