Before:
  runtime ale_linters/sql/sqlfluff.vim

After:
  call ale#linter#Reset()

Execute(The sqlfluff handler should handle basic warnings):
  AssertEqual
  \ [
  \   {
  \     'filename': 'schema.sql',
  \     'lnum': 1,
  \     'col': 8,
  \     'type': 'W',
  \     'code': 'L010',
  \     'text': 'Keywords must be consistently upper case.',
  \   },
  \   {
  \     'filename': 'schema.sql',
  \     'lnum': 13,
  \     'col': 2,
  \     'type': 'W',
  \     'code': 'L003',
  \     'text': 'Expected 1 indentation, found 0 [compared to line 12]',
  \   },
  \   {
  \     'filename': 'schema.sql',
  \     'lnum': 16,
  \     'col': 1,
  \     'type': 'W',
  \     'code': 'L009',
  \     'text': 'Files must end with a single trailing newline.',
  \   },
  \ ],
  \ ale_linters#sql#sqlfluff#Handle(1, [
  \    '[{"filepath": "schema.sql", "violations": [{"line_no": 1, "line_pos": 8, "code": "L010", "description": "Keywords must be consistently upper case."}, {"line_no": 13, "line_pos": 2, "code": "L003", "description": "Expected 1 indentation, found 0 [compared to line 12]"}, {"line_no": 16, "line_pos": 1, "code": "L009", "description": "Files must end with a single trailing newline."}]}]',
  \ ])