Before:
  call ale#test#SetDirectory('/testplugin/test/handler')

After:
  call ale#test#RestoreDirectory()

Execute(Basic errors should be handled by cppcheck):
  call ale#test#SetFilename('test.cpp')

  AssertEqual
  \ [
  \   {
  \     'lnum': 974,
  \     'col' : 6,
  \     'type': 'E',
  \     'sub_type': '',
  \     'text': 'Array ''n[3]'' accessed at index 3, which is out of bounds.',
  \     'code': 'arrayIndexOutOfBounds'
  \   },
  \   {
  \     'lnum': 1185,
  \     'col' : 10,
  \     'type': 'W',
  \     'sub_type': 'style',
  \     'text': 'The scope of the variable ''indxStr'' can be reduced.',
  \     'code': 'variableScope'
  \   },
  \ ],
  \ ale#handlers#cppcheck#HandleCppCheckFormat(bufnr(''), [
  \ 'test.cpp:974:6: error: Array ''n[3]'' accessed at index 3, which is out of bounds. [arrayIndexOutOfBounds]\',
  \ '    n[3]=3;',
  \ '     ^',
  \ 'test.cpp:1185:10: style: The scope of the variable ''indxStr'' can be reduced. [variableScope]\',
  \ '    char indxStr[16];',
  \ '         ^',
  \ ])

  AssertEqual
  \ [
  \   {
  \     'lnum': 974,
  \     'col' : 1,
  \     'type': 'E',
  \     'sub_type': '',
  \     'text': 'inconclusive Array ''n[3]'' accessed at index 3, which is out of bounds.',
  \     'code': 'arrayIndexOutOfBounds'
  \   },
  \   {
  \     'lnum': 1185,
  \     'col' : 1,
  \     'type': 'W',
  \     'sub_type': 'style',
  \     'text': 'The scope of the variable ''indxStr'' can be reduced.',
  \     'code': 'variableScope'
  \   },
  \ ],
  \ ale#handlers#cppcheck#HandleCppCheckFormat(bufnr(''), [
  \ 'test.cpp:974:{column}: error:inconclusive Array ''n[3]'' accessed at index 3, which is out of bounds. [arrayIndexOutOfBounds]\',
  \ '    n[3]=3;',
  \ '     ^',
  \ 'test.cpp:1185:{column}: style:{inconclusive:inconclusive} The scope of the variable ''indxStr'' can be reduced. [variableScope]\',
  \ '    char indxStr[16];',
  \ '         ^',
  \ ])

  AssertEqual
  \ [
  \   {
  \     'lnum': 1,
  \     'col' : 16,
  \     'type': 'W',
  \     'sub_type': 'style',
  \     'text': 'misra violation (use --rule-texts=<file> to get proper output)',
  \     'code': 'misra-c2012-2.7'
  \   },
  \ ],
  \ ale#handlers#cppcheck#HandleCppCheckFormat(bufnr(''), [
  \ 'test.cpp:1:16: style: misra violation (use --rule-texts=<file> to get proper output) [misra-c2012-2.7]\',
  \ 'void test( int parm ) {}',
  \ '               ^',
  \ ])

Execute(Problems from other files should be ignored by cppcheck):
  call ale#test#SetFilename('test.cpp')

  AssertEqual
  \ [
  \ ],
  \ ale#handlers#cppcheck#HandleCppCheckFormat(bufnr(''), [
  \ 'bar.cpp:974:6: error: Array ''n[3]'' accessed at index 3, which is out of bounds. [arrayIndexOutOfBounds]\',
  \ '    n[3]=3;',
  \ '     ^',
  \ ])