#505 - Do not lint files on enter if the option for linting when the filetype changed is on

test/sign/test_sign_placement.vader

@@ -3,6 +3,9 @@ Before:
 
   let g:ale_set_signs = 1
 
+  call ale#linter#Reset()
+  sign unplace *
+
   function! GenerateResults(buffer, output)
     return [
     \ {

test/test_lint_on_filetype_changed.vader

@@ -3,6 +3,8 @@ Before:
 
   let g:queue_calls = []
 
+  unlet! b:ale_lint_on_enter
+
   function! ale#Queue(...)
     call add(g:queue_calls, a:000)
   endfunction
@@ -10,6 +12,7 @@ Before:
 After:
   Restore
 
+  unlet! b:ale_lint_on_enter
   unlet! g:queue_calls
 
   " Reload the ALE code to load the real function again.
@@ -45,3 +48,27 @@ Execute(Linting should be queued when the filetype changes):
   call ale#events#FileTypeEvent(bufnr(''), 'bazboz')
 
   AssertEqual [[300, 'lint_file', bufnr('')]], g:queue_calls
+
+Execute(Linting shouldn't be done when the original filetype was blank and linting on enter is off):
+  let b:ale_lint_on_enter = 0
+  let b:ale_original_filetype = ''
+
+  call ale#events#FileTypeEvent(bufnr(''), 'bazboz')
+
+  AssertEqual [], g:queue_calls
+
+Execute(Linting should be done when the original filetype was blank and linting on enter is on):
+  let b:ale_lint_on_enter = 1
+  let b:ale_original_filetype = ''
+
+  call ale#events#FileTypeEvent(bufnr(''), 'bazboz')
+
+  AssertEqual [[300, 'lint_file', bufnr('')]], g:queue_calls
+
+Execute(The new filetype should become the "original" one if the original was blank and linting on enter is off):
+  let b:ale_lint_on_enter = 0
+  let b:ale_original_filetype = ''
+
+  call ale#events#FileTypeEvent(bufnr(''), 'bazboz')
+
+  AssertEqual 'bazboz', b:ale_original_filetype