patch 7.4.1923

Problem:    Command line editing is not tested much.
Solution:   Add tests for expanding the file name and 'wildmenu'.

src/testdir/test_cmdline.vim

@@ -0,0 +1,26 @@
+" Tests for editing the command line.
+
+func Test_complete_tab()
+  call writefile(['testfile'], 'Xtestfile')
+  call feedkeys(":e Xtest\t\r", "tx")
+  call assert_equal('testfile', getline(1))
+  call delete('Xtestfile')
+endfunc
+
+func Test_complete_list()
+  " We can't see the output, but at least we check the code runs properly.
+  call feedkeys(":e test\<C-D>\r", "tx")
+  call assert_equal('test', expand('%:t'))
+endfunc
+
+func Test_complete_wildmenu()
+  call writefile(['testfile1'], 'Xtestfile1')
+  call writefile(['testfile2'], 'Xtestfile2')
+  set wildmenu
+  call feedkeys(":e Xtest\t\t\r", "tx")
+  call assert_equal('testfile2', getline(1))
+
+  call delete('Xtestfile1')
+  call delete('Xtestfile2')
+  set nowildmenu
+endfunc