1 files changed, 67 insertions, 0 deletions
diff --git a/test/functional/legacy/backspace_opt_spec.lua b/test/functional/legacy/backspace_opt_spec.lua
new file mode 100644
index 0000000000..b40019a410
--- /dev/null
+++ b/test/functional/legacy/backspace_opt_spec.lua
@@ -0,0 +1,67 @@
+local helpers = require('test.functional.helpers')
+local call, clear = helpers.call, helpers.clear
+local source, eq, nvim = helpers.source, helpers.eq, helpers.meths
+
+describe("test 'backspace' settings", function()
+  before_each(function()
+    clear()
+
+    source([[
+      func Exec(expr)
+        let str=''
+        try
+          exec a:expr
+        catch /.*/
+          let str=v:exception
+        endtry
+        return str
+      endfunc
+
+      func Test_backspace_option()
+        set backspace=
+        call assert_equal('', &backspace)
+        set backspace=indent
+        call assert_equal('indent', &backspace)
+        set backspace=eol
+        call assert_equal('eol', &backspace)
+        set backspace=start
+        call assert_equal('start', &backspace)
+        " Add the value
+        set backspace=
+        set backspace=indent
+        call assert_equal('indent', &backspace)
+        set backspace+=eol
+        call assert_equal('indent,eol', &backspace)
+        set backspace+=start
+        call assert_equal('indent,eol,start', &backspace)
+        " Delete the value
+        set backspace-=indent
+        call assert_equal('eol,start', &backspace)
+        set backspace-=start
+        call assert_equal('eol', &backspace)
+        set backspace-=eol
+        call assert_equal('', &backspace)
+        " Check the error
+        call assert_equal(0, match(Exec('set backspace=ABC'), '.*E474'))
+        call assert_equal(0, match(Exec('set backspace+=def'), '.*E474'))
+        " NOTE: Vim doesn't check following error...
+        "call assert_equal(0, match(Exec('set backspace-=ghi'), '.*E474'))
+
+        " Check backwards compatibility with version 5.4 and earlier
+        set backspace=0
+        call assert_equal('0', &backspace)
+        set backspace=1
+        call assert_equal('1', &backspace)
+        set backspace=2
+        call assert_equal('2', &backspace)
+        call assert_false(match(Exec('set backspace=3'), '.*E474'))
+        call assert_false(match(Exec('set backspace=10'), '.*E474'))
+      endfunc
+    ]])
+  end)
+
+  it('works', function()
+    call('Test_backspace_option')
+    eq({}, nvim.get_vvar('errors'))
+  end)
+end)