new file mode 100644
--- /dev/null
+++ b/src/testdir/test_windows_home.vim
@@ -0,0 +1,124 @@
+" Test for $HOME on Windows.
+
+if !has('win32')
+  finish
+endif
+
+let s:env = {}
+
+func s:restore_env()
+  for i in keys(s:env)
+    exe 'let ' . i . '=s:env["' . i . '"]'
+  endfor
+endfunc
+
+func s:save_env(...)
+  for i in a:000
+    exe 'let s:env["' . i . '"]=' . i
+  endfor
+endfunc
+
+func s:unlet_env(...)
+  for i in a:000
+    exe 'let ' . i . '=""'
+  endfor
+endfunc
+
+func CheckHomeIsMissingFromSubprocessEnvironment()
+  silent! let out = system('set')
+  let env = filter(split(out, "\n"), 'v:val=~"^HOME="')
+  call assert_equal(0, len(env))
+endfunc
+
+func CheckHomeIsInSubprocessEnvironment(exp)
+  silent! let out = system('set')
+  let env = filter(split(out, "\n"), 'v:val=~"^HOME="')
+  let home = len(env) == 0 ? "" : substitute(env[0], '[^=]\+=', '', '')
+  call assert_equal(a:exp, home)
+endfunc
+
+func CheckHome(exp, ...)
+  "call assert_equal(a:exp, $HOME)
+  "call assert_equal(a:exp, expand('~', ':p'))
+  if !a:0
+    call CheckHomeIsMissingFromSubprocessEnvironment()
+  else
+    call CheckHomeIsInSubprocessEnvironment(a:exp)
+  endif
+endfunc
+
+func TestWindowsHome()
+  command! -nargs=* SaveEnv call <SID>save_env(<f-args>)
+  command! -nargs=* RestoreEnv call <SID>restore_env()
+  command! -nargs=* UnletEnv call <SID>unlet_env(<f-args>)
+
+  SaveEnv $HOME $USERPROFILE $HOMEDRIVE $HOMEPATH
+  try
+    RestoreEnv
+    UnletEnv $HOME $USERPROFILE $HOMEPATH
+    let $HOMEDRIVE = 'C:'
+    call CheckHome('C:\')
+
+    RestoreEnv
+    UnletEnv $HOME $USERPROFILE
+    let $HOMEDRIVE = 'C:'
+    let $HOMEPATH = '\foobar'
+    call CheckHome('C:\foobar')
+
+    RestoreEnv
+    UnletEnv $HOME $HOMEDRIVE $HOMEPATH
+    let $USERPROFILE = 'C:\foo'
+    call CheckHome('C:\foo')
+
+    RestoreEnv
+    UnletEnv $HOME
+    let $USERPROFILE = 'C:\foo'
+    let $HOMEDRIVE = 'C:'
+    let $HOMEPATH = '\baz'
+    call CheckHome('C:\foo')
+
+    RestoreEnv
+    let $HOME = 'C:\bar'
+    let $USERPROFILE = 'C:\foo'
+    let $HOMEDRIVE = 'C:'
+    let $HOMEPATH = '\baz'
+    call CheckHome('C:\bar', 1)
+
+    RestoreEnv
+    let $HOME = '%USERPROFILE%\bar'
+    let $USERPROFILE = 'C:\foo'
+    let $HOMEDRIVE = 'C:'
+    let $HOMEPATH = '\baz'
+    call CheckHome('%USERPROFILE%\bar', 1)
+
+    RestoreEnv
+    let $HOME = '%USERPROFILE'
+    let $USERPROFILE = 'C:\foo'
+    let $HOMEDRIVE = 'C:'
+    let $HOMEPATH = '\baz'
+    call CheckHome('%USERPROFILE', 1)
+
+    RestoreEnv
+    let $HOME = 'C:\%USERPROFILE%'
+    let $USERPROFILE = 'C:\foo'
+    let $HOMEDRIVE = 'C:'
+    let $HOMEPATH = '\baz'
+    call CheckHome('C:\%USERPROFILE%', 1)
+
+    if has('channel')
+      RestoreEnv
+      UnletEnv $HOME
+      let env = ''
+      let job = job_start('cmd /c set', {'out_cb': {ch,x->[env,execute('let env=x')]}})
+      sleep 1
+      let env = filter(split(env, "\n"), 'v:val=="HOME"')
+      let home = len(env) == 0 ? "" : env[0]
+      call assert_equal('', home)
+    endif
+  finally
+    RestoreEnv
+    delcommand SaveEnv
+    delcommand RestoreEnv
+    delcommand UnletEnv
+  endtry
+endfunc