legacy tests: migrate test54

src/nvim/testdir/test54.in

@@ -1,22 +0,0 @@
-Some tests for buffer-local autocommands
-
-STARTTEST
-:so small.vim
-:e xx
-:if has("vms")
-: !del test.out.*
-: au BufLeave <buffer> :!write sys$output "buffer-local autommand in %" > test.out
-:else
-: !rm -f test.out
-: au BufLeave <buffer> :!echo buffer-local autommand in %>> test.out
-:endif
-:e somefile           " here, autocommand for xx shall write test.out 
-:                     " but autocommand shall not apply to buffer named <buffer>
-:bwipe xx             " here, autocommand shall be auto-deleted
-:e xx                 " nothing shall be written
-:e somefile           " nothing shall be written
-:qa!
-ENDTEST
-
-start of test file xx
-end of test file xx

src/nvim/testdir/test54.ok

@@ -1 +0,0 @@
-buffer-local autommand in xx

test/functional/legacy/054_buffer_local_autocommands_spec.lua

@@ -0,0 +1,33 @@
+-- Some tests for buffer-local autocommands
+
+local helpers = require('test.functional.helpers')
+local clear, execute, eq = helpers.clear, helpers.execute, helpers.eq
+local curbuf_contents = helpers.curbuf_contents
+
+describe('BufLeave <buffer>', function()
+  setup(clear)
+
+  it('is working', function()
+    execute('w! xx')
+    execute('au BufLeave <buffer> norm Ibuffer-local autocommand')
+    execute('au BufLeave <buffer> update')
+    
+    -- Here, autocommand for xx shall append a line
+    -- But autocommand shall not apply to buffer named <buffer> 
+    execute('e somefile')
+
+    -- Here, autocommand shall be auto-deleted
+    execute('bwipe xx')
+    
+    -- Nothing shall be written
+    execute('e xx')
+    execute('e somefile')
+    execute('e xx')
+
+    eq('buffer-local autocommand', curbuf_contents())
+  end)
+
+  teardown(function()
+    os.remove('xx')
+  end)
+end)