tests: Fix an further simplify migrated test 61.

:undojoin can only be used inside scripts and command chains.  So it has to be
tested inside an explicit `source()` call.

Also add a new test case for the different behavior when sourceing normal mode
commands from a script or inserting them interactively.

test/functional/legacy/061_undo_tree_spec.lua

@@ -5,84 +5,89 @@ local feed, insert, source, eq, eval, clear, execute, expect, wait =
   helpers.feed, helpers.insert, helpers.source, helpers.eq, helpers.eval,
   helpers.clear, helpers.execute, helpers.expect, helpers.wait
 
-local expect_empty_buffer = function()
+local function expect_empty_buffer()
   -- The space will be removed by helpers.dedent but is needed as dedent will
   -- throw an error if it can not find the common indent of the given lines.
-  expect(' ')
+  return expect(' ')
+end
+local function expect_line(line)
+  return eq(line, eval('getline(".")'))
+end
+local function write_file(name, text)
+  local file = io.open(name, 'w')
+  file:write(text)
+  file:flush()
+  file:close()
 end
 
+
 describe('the undo tree', function()
-  setup(clear)
+  setup(function()
+    clear()
+    write_file('Xtest.source', 'o1\x1ba2\x12=string(123)\n\x1b')
+    write_file('Xtest0', '\n123456789\n')
+  end)
   teardown(function()
+    os.remove('Xtest0')
     os.remove('Xtest')
+    os.remove('Xtest.source')
   end)
 
   it('is working', function()
+    execute('e Xtest0')
     -- Assert that no undo history is present.
     eq({}, eval('undotree().entries'))
-    insert([[
-      
-      123456789]])
-
-    -- Clear the undo history after the insertion (see :h clear-undo)
-    execute('let old_undolevels = &undolevels')
-    execute('set undolevels=-1')
-    feed('a <BS><Esc>') 
-    execute('let &undolevels = old_undolevels')
-    execute('unlet old_undolevels')
-    eq({}, eval('undotree().entries'))
-
     -- Delete three characters and undo.
     feed('Gxxx')
-    eq('456789', eval('getline(".")'))
+    expect_line('456789')
     feed('g-')
-    eq('3456789', eval('getline(".")'))
+    expect_line('3456789')
     feed('g-')
-    eq('23456789', eval('getline(".")'))
+    expect_line('23456789')
     feed('g-')
-    eq('123456789', eval('getline(".")'))
+    expect_line('123456789')
     feed('g-')
-    eq('123456789', eval('getline(".")'))
+    expect_line('123456789')
 
     -- Delete three other characters and go back in time step by step.
     feed('$xxx')
-    eq('123456', eval('getline(".")'))
+    expect_line('123456')
     execute('sleep 1')
     wait()
     feed('g-')
-    eq('1234567', eval('getline(".")'))
+    expect_line('1234567')
     feed('g-')
-    eq('12345678', eval('getline(".")'))
+    expect_line('12345678')
     feed('g-')
-    eq('456789', eval('getline(".")'))
+    expect_line('456789')
     feed('g-')
-    eq('3456789', eval('getline(".")'))
+    expect_line('3456789')
     feed('g-')
-    eq('23456789', eval('getline(".")'))
+    expect_line('23456789')
     feed('g-')
-    eq('123456789', eval('getline(".")'))
+    expect_line('123456789')
     feed('g-')
-    eq('123456789', eval('getline(".")'))
+    expect_line('123456789')
     feed('g-')
-    eq('123456789', eval('getline(".")'))
+    expect_line('123456789')
     feed('10g+')
-    eq('123456', eval('getline(".")'))
+    expect_line('123456')
 
-    -- Delay for three seconds and go some seconds forward and backward.
+    -- Delay for two seconds and go some seconds forward and backward.
     execute('sleep 2')
     wait()
     feed('Aa<esc>')
     feed('Ab<esc>')
     feed('Ac<esc>')
-    eq('123456abc', eval('getline(".")'))
-    execute('ear 1s')
-    eq('123456', eval('getline(".")'))
-    execute('ear 3s')
-    eq('123456789', eval('getline(".")'))
+    expect_line('123456abc')
+    execute('earlier 1s')
+    expect_line('123456')
+    execute('earlier 3s')
+    expect_line('123456789')
     execute('later 1s')
-    eq('123456', eval('getline(".")'))
+    expect_line('123456')
     execute('later 1h')
-    eq('123456abc', eval('getline(".")'))
+    expect_line('123456abc')
 
     -- Test that setting 'ul' breaks change blocks, we need to use source() in
     -- order to test this, as interactive changes are not grouped.
@@ -123,13 +128,15 @@ describe('the undo tree', function()
     -- Test undojoin.
     feed('Goaaaa<esc>')
     feed('obbbb<esc>u')
-    eq('aaaa', eval('getline(".")'))
-    feed('obbbb<esc>')
-    execute('undojoin')
-    feed('occcc<esc>u')
-    -- TODO At this point the original test will write "aaaa" to test.out.
-    -- Why is the line "bbbb" here?
-    eq('bbbb', eval('getline(".")'))
+    expect_line('aaaa')
+    source([[
+      normal obbbb
+      set ul=100
+      undojoin
+      normal occcc
+    ]])
+    feed('u')
+    expect_line('aaaa')
 
     execute('e! Xtest')
     feed('ione one one<esc>')
@@ -195,7 +202,32 @@ describe('the undo tree', function()
       c
       12]])
     feed('od<esc>')
-    feed('o1<esc>a2<C-R>=string(123)<cr><esc>')
+    -- The file Xtest.source is written during setup.  It contains this text
+    -- (nvim like escape sequences interpreted):
+    -- o1<esc>a2<C-R>=string(123)<cr><esc>
+    execute('so! Xtest.source')
+    expect([[
+      
+      a
+      b
+      1
+      c
+      12
+      d
+      12123]])
+    feed('u')
+    expect([[
+      
+      a
+      b
+      1
+      c
+      12
+      d]])
+    -- The above behaviour was tested in the legacy vim test because the
+    -- legacy tests were executed with ':so!'.  The behavior differs for
+    -- interactive use (even in vim, where the result was the same):
+    feed(io.open('Xtest.source'):read('*all'))
     expect([[
       
       a
@@ -205,13 +237,6 @@ describe('the undo tree', function()
       12
       d
       12123]])
-
-    -- TODO there is a difference between the original test and this test at
-    -- this point.  The original tests expects the last line to go away after
-    -- the undo.  I do not know why this should be the case as the "o" and "a"
-    -- above are seperate changes.  I was able to confirm this manually with
-    -- vim and nvim.  Both end up in this state (treat "o" and "a" as two
-    -- edits).
     feed('u')
     expect([[