diff --git a/src/testdir/test_farsi.vim b/src/testdir/test_farsi.vim
new file mode 100644
index 0000000..81afce2
--- /dev/null
+++ b/src/testdir/test_farsi.vim
@@ -0,0 +1,84 @@
+" Simplistic testing of Farsi mode.
+
+if !has('farsi')
+  finish
+endif
+" Farsi uses a single byte encoding.
+set enc=latin1
+
+func Test_farsi_toggle()
+  new
+
+  set altkeymap
+  call assert_equal(0, &fkmap)
+  call assert_equal(0, &rl)
+  call feedkeys("\<F8>", 'x')
+  call assert_equal(1, &fkmap)
+  call assert_equal(1, &rl)
+  call feedkeys("\<F8>", 'x')
+  call assert_equal(0, &fkmap)
+  call assert_equal(0, &rl)
+
+  set rl
+  " conversion from Farsi 3342 to Farsi VIM.
+  call setline(1, join(map(range(0x80, 0xff), 'nr2char(v:val)'), ''))
+  call feedkeys("\<F9>", 'x')
+  let exp = [0xfc, 0xf8, 0xc1, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
+	   \ 0xc8, 0xc9, 0xca, 0xd0, 0xd1, 0xd2, 0xd3, 0xd6,
+	   \ 0xd6, 0xd6, 0xd7, 0xd7, 0xd7, 0xd8, 0xd9, 0xda,
+	   \ 0xdb, 0xdc, 0xdc, 0xc1, 0xdd, 0xde, 0xe0, 0xe0,
+	   \ 0xe1, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6,
+	   \ 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae,
+	   \ 0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
+	   \ 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe,
+	   \ 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6,
+	   \ 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce,
+	   \ 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6,
+	   \ 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde,
+	   \ 0xdf, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6,
+	   \ 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xfb, 0xfb, 0xfe,
+	   \ 0xfe, 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6,
+	   \ 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xe1,
+           \ ]
+  call assert_equal(join(map(exp, 'nr2char(v:val)'), ''), getline(1))
+
+  " conversion from Farsi VIM to Farsi 3342.
+  call setline(1, join(map(range(0x80, 0xff), 'nr2char(v:val)'), ''))
+  call feedkeys("\<F9>", 'x')
+  let exp = [0xfc, 0xf8, 0xc1, 0x83, 0x84, 0x85, 0x86, 0x87,
+	   \ 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x90,
+	   \ 0x90, 0x90, 0x92, 0x93, 0x93, 0x95, 0x96, 0x97,
+	   \ 0x98, 0xdc, 0x9a, 0x9b, 0x9c, 0x9e, 0x9e, 0xff,
+	   \ 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+	   \ 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+	   \ 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+	   \ 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
+	   \ 0xc0, 0xc1, 0xc2, 0x83, 0x84, 0x85, 0x86, 0x87,
+	   \ 0x88, 0x89, 0x8a, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
+	   \ 0x8b, 0x8c, 0x8d, 0x8e, 0xd4, 0xd5, 0x90, 0x93,
+	   \ 0x95, 0x96, 0x97, 0x98, 0x99, 0x9b, 0x9c, 0xdf,
+	   \ 0x9d, 0xff, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
+	   \ 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xec, 0xee, 0xef,
+	   \ 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
+	   \ 0xf8, 0xf9, 0xfa, 0xec, 0x80, 0xfd, 0xee, 0xff,
+           \ ]
+  call assert_equal(join(map(exp, 'nr2char(v:val)'), ''), getline(1))
+
+  bwipe!
+endfunc
+
+func Test_farsi_map()
+  new
+
+  set altkeymap
+  set rl
+  " RHS of mapping is reversed.
+  imap xyz abc
+  call feedkeys("axyz\<Esc>", 'tx')
+  call assert_equal('cba', getline(1))
+
+  set norl
+  iunmap xyz
+  set noaltkeymap
+  bwipe!
+endfunc