Cover the SaveEvent function with a test

test/test_lint_file_linters.vader

@@ -224,3 +224,30 @@ Execute(Linter errors from files should be kept when no other linters are run):
   \   'type': 'E',
   \ },
   \], GetSimplerLoclist()
+
+Execute(The Save event should respect the buffer number):
+  let g:ale_linters = {'foobar': ['lint_file_linter']}
+  Assert filereadable(expand('%:p')), 'The file was not readable'
+
+  call ale#events#SaveEvent(bufnr('') + 1)
+
+  " We shouldn't get any prblems yet.
+  AssertEqual [], GetSimplerLoclist()
+
+  call ale#events#SaveEvent(bufnr(''))
+
+  " We should get them now we used the right buffer number.
+  AssertEqual [
+  \ {
+  \   'lnum': 1,
+  \   'col': 3,
+  \   'text': 'file warning',
+  \   'type': 'W',
+  \ },
+  \ {
+  \   'lnum': 2,
+  \   'col': 3,
+  \   'text': 'file error',
+  \   'type': 'E',
+  \ },
+  \], GetSimplerLoclist()