3 files changed, 71 insertions, 4 deletions
diff --git a/test/functional/helpers.lua b/test/functional/helpers.lua
index 7de1d0f2c6..880cb6546c 100644
--- a/test/functional/helpers.lua
+++ b/test/functional/helpers.lua
@@ -195,7 +195,7 @@ local function dedent(str)
       indent = line_indent
     end
   end
-  if #indent == 0 then
+  if indent == nil or #indent == 0 then
     -- no minimum common indent
     return str
   end
diff --git a/test/functional/normal/undo_spec.lua b/test/functional/normal/undo_spec.lua
new file mode 100644
index 0000000000..55429f2e1e
--- /dev/null
+++ b/test/functional/normal/undo_spec.lua
@@ -0,0 +1,61 @@
+local helpers = require('test.functional.helpers')(after_each)
+
+local clear = helpers.clear
+local execute = helpers.execute
+local expect = helpers.expect
+local feed = helpers.feed
+local insert = helpers.insert
+
+describe('u CTRL-R g- g+', function()
+  before_each(clear)
+
+  local function create_history(num_steps)
+    if num_steps == 0 then return end
+    insert('1')
+    if num_steps == 1 then return end
+    feed('o2<esc>')
+    feed('o3<esc>')
+    feed('u')
+    if num_steps == 2 then return end
+    feed('o4<esc>')
+    if num_steps == 3 then return end
+    feed('u')
+  end
+
+  local function undo_and_redo(hist_pos, undo, redo, expect_str)
+    execute('enew!')
+    create_history(hist_pos)
+    local cur_contents = helpers.curbuf_contents()
+    feed(undo)
+    expect(expect_str)
+    feed(redo)
+    expect(cur_contents)
+  end
+
+  -- TODO Look for message saying 'Already at oldest change'
+  it('does nothing when no changes have happened', function()
+    undo_and_redo(0, 'u', '<C-r>', '')
+    undo_and_redo(0, 'g-', 'g+', '')
+  end)
+  it('undoes a change when at a leaf', function()
+    undo_and_redo(1, 'u', '<C-r>', '')
+    undo_and_redo(1, 'g-', 'g+', '')
+  end)
+  it('undoes a change when in a non-leaf', function()
+    undo_and_redo(2, 'u', '<C-r>', '1')
+    undo_and_redo(2, 'g-', 'g+', '1')
+  end)
+  it('undoes properly around a branch point', function()
+    undo_and_redo(3, 'u', '<C-r>', [[
+      1
+      2]])
+    undo_and_redo(3, 'g-', 'g+', [[
+      1
+      2
+      3]])
+  end)
+  it('can find the previous sequence after undoing to a branch', function()
+    undo_and_redo(4, 'u', '<C-r>', '1')
+    undo_and_redo(4, 'g-', 'g+', '1')
+  end)
+end)
diff --git a/test/functional/ui/inccommand_spec.lua b/test/functional/ui/inccommand_spec.lua
index 41ebfd2334..6da22b6a3a 100644
--- a/test/functional/ui/inccommand_spec.lua
+++ b/test/functional/ui/inccommand_spec.lua
@@ -352,6 +352,14 @@ describe(":substitute, 'inccommand' preserves undo", function()
 
     feed("2u")
     feed(substring .. "<esc>")
+    expect([[
+      1]])
+    feed("g-")
+    expect([[
+      ]])
+    feed("g+")
+    expect([[
+      1]])
     feed("<c-r>")
     expect([[
       1
@@ -374,9 +382,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
       2]])
   end
 
-  -- TODO(vim): This does not work, even in Vim.
-  -- Waiting for fix (perhaps from upstream).
-  pending("at a non-leaf of the undo tree", function()
+  it("at a non-leaf of the undo tree", function()
    for _, case in pairs(cases) do
      for _, str in pairs(substrings) do
        for _, redoable in pairs({true}) do