Support pylama for python (#2266)

* Add pylama for python
* Consolidate python traceback handling

ale_linters/python/flake8.vim

@@ -74,15 +74,11 @@ let s:end_col_pattern_map = {
 \}
 
 function! ale_linters#python#flake8#Handle(buffer, lines) abort
-    for l:line in a:lines[:10]
-        if match(l:line, '^Traceback') >= 0
-            return [{
-            \   'lnum': 1,
-            \   'text': 'An exception was thrown. See :ALEDetail',
-            \   'detail': join(a:lines, "\n"),
-            \}]
+    let l:output = ale#python#HandleTraceback(a:lines, 10)
+
+    if !empty(l:output)
+        return l:output
     endif
-    endfor
 
     " Matches patterns line the following:
     "
@@ -90,7 +86,6 @@ function! ale_linters#python#flake8#Handle(buffer, lines) abort
     "
     " stdin:6:6: E111 indentation is not a multiple of four
     let l:pattern = '\v^[a-zA-Z]?:?[^:]+:(\d+):?(\d+)?: ([[:alnum:]]+):? (.*)$'
-    let l:output = []
 
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
         let l:code = l:match[3]

ale_linters/python/pylama.vim

@@ -0,0 +1,94 @@
+" Author: Kevin Locke <kevin@kevinlocke.name>
+" Description: pylama for python files
+
+call ale#Set('python_pylama_executable', 'pylama')
+call ale#Set('python_pylama_options', '')
+call ale#Set('python_pylama_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('python_pylama_auto_pipenv', 0)
+call ale#Set('python_pylama_change_directory', 1)
+
+function! ale_linters#python#pylama#GetExecutable(buffer) abort
+    if (ale#Var(a:buffer, 'python_auto_pipenv') || ale#Var(a:buffer, 'python_pylama_auto_pipenv'))
+    \ && ale#python#PipenvPresent(a:buffer)
+        return 'pipenv'
+    endif
+
+    return ale#python#FindExecutable(a:buffer, 'python_pylama', ['pylama'])
+endfunction
+
+function! ale_linters#python#pylama#GetCommand(buffer) abort
+    let l:cd_string = ''
+
+    if ale#Var(a:buffer, 'python_pylama_change_directory')
+        " Pylama loads its configuration from the current directory only, and
+        " applies file masks using paths relative to the current directory.
+        " Run from project root, if found, otherwise buffer dir.
+        let l:project_root = ale#python#FindProjectRoot(a:buffer)
+        let l:cd_string = l:project_root isnot# ''
+        \   ? ale#path#CdString(l:project_root)
+        \   : ale#path#BufferCdString(a:buffer)
+    endif
+
+    let l:executable = ale_linters#python#pylama#GetExecutable(a:buffer)
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run pylama'
+    \   : ''
+
+    return l:cd_string
+    \   . ale#Escape(l:executable) . l:exec_args
+    \   . ale#Pad(ale#Var(a:buffer, 'python_pylama_options'))
+    \   . ' %t'
+endfunction
+
+function! ale_linters#python#pylama#Handle(buffer, lines) abort
+    if empty(a:lines)
+        return []
+    endif
+
+    let l:output = ale#python#HandleTraceback(a:lines, 1)
+    let l:pattern = '\v^.{-}:([0-9]+):([0-9]+): +%(([A-Z][0-9]+):? +)?(.*)$'
+
+    " First letter of error code is a pylint-compatible message type
+    " http://pylint.pycqa.org/en/latest/user_guide/output.html#source-code-analysis-section
+    " D is for Documentation (pydocstyle)
+    let l:pylint_type_to_ale_type = {
+    \   'I': 'I',
+    \   'R': 'W',
+    \   'C': 'W',
+    \   'W': 'W',
+    \   'E': 'E',
+    \   'F': 'E',
+    \   'D': 'W',
+    \}
+    let l:pylint_type_to_ale_sub_type = {
+    \   'R': 'style',
+    \   'C': 'style',
+    \   'D': 'style',
+    \}
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        " Ignore C0103 for module name from temporary path (%t) which may not
+        " comply with module-rgx.
+        if l:match[3] is# 'C0103' && l:match[4] =~# '^Module name '
+            continue
+        endif
+
+        call add(l:output, {
+        \   'lnum': str2nr(l:match[1]),
+        \   'col': str2nr(l:match[2]),
+        \   'code': l:match[3],
+        \   'type': get(l:pylint_type_to_ale_type, l:match[3][0], 'W'),
+        \   'sub_type': get(l:pylint_type_to_ale_sub_type, l:match[3][0], ''),
+        \   'text': l:match[4],
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('python', {
+\   'name': 'pylama',
+\   'executable_callback': 'ale_linters#python#pylama#GetExecutable',
+\   'command_callback': 'ale_linters#python#pylama#GetCommand',
+\   'callback': 'ale_linters#python#pylama#Handle',
+\})

ale_linters/python/vulture.vim

@@ -46,19 +46,14 @@ endfunction
 
 
 function! ale_linters#python#vulture#Handle(buffer, lines) abort
-    for l:line in a:lines[:10]
-        if match(l:line, '^Traceback') >= 0
-            return [{
-            \   'lnum': 1,
-            \   'text': 'An exception was thrown. See :ALEDetail',
-            \   'detail': join(a:lines, "\n"),
-            \}]
+    let l:output = ale#python#HandleTraceback(a:lines, 10)
+
+    if !empty(l:output)
+        return l:output
     endif
-    endfor
 
     " Matches patterns line the following:
     let l:pattern = '\v^([a-zA-Z]?:?[^:]+):(\d+): (.*)$'
-    let l:output = []
     let l:dir = s:GetDir(a:buffer)
 
     for l:match in ale#util#GetMatches(a:lines, l:pattern)

autoload/ale/python.vim

@@ -27,6 +27,7 @@ function! ale#python#FindProjectRootIni(buffer) abort
         \|| filereadable(l:path . '/pycodestyle.cfg')
         \|| filereadable(l:path . '/flake8.cfg')
         \|| filereadable(l:path . '/.flake8rc')
+        \|| filereadable(l:path . '/pylama.ini')
         \|| filereadable(l:path . '/Pipfile')
         \|| filereadable(l:path . '/Pipfile.lock')
             return l:path
@@ -110,6 +111,44 @@ function! ale#python#FindExecutable(buffer, base_var_name, path_list) abort
     return ale#Var(a:buffer, a:base_var_name . '_executable')
 endfunction
 
+" Handle traceback.print_exception() output starting in the first a:limit lines.
+function! ale#python#HandleTraceback(lines, limit) abort
+    let l:nlines = len(a:lines)
+    let l:limit = a:limit > l:nlines ? l:nlines : a:limit
+    let l:start = 0
+
+    while l:start < l:limit
+        if a:lines[l:start] is# 'Traceback (most recent call last):'
+            break
+        endif
+
+        let l:start += 1
+    endwhile
+
+    if l:start >= l:limit
+        return []
+    endif
+
+    let l:end = l:start + 1
+
+    " Traceback entries are always prefixed with 2 spaces.
+    " SyntaxError marker (if present) is prefixed with at least 4 spaces.
+    " Final exc line starts with exception class name (never a space).
+    while l:end < l:nlines && a:lines[l:end][0] is# ' '
+        let l:end += 1
+    endwhile
+
+    let l:exc_line = l:end < l:nlines
+    \   ? a:lines[l:end]
+    \   : 'An exception was thrown.'
+
+    return [{
+    \   'lnum': 1,
+    \   'text': l:exc_line . ' (See :ALEDetail)',
+    \   'detail': join(a:lines[(l:start):(l:end)], "\n"),
+    \}]
+endfunction
+
 " Detects whether a pipenv environment is present.
 function! ale#python#PipenvPresent(buffer) abort
     return findfile('Pipfile.lock', expand('#' . a:buffer . ':p:h') . ';') isnot# ''

doc/ale-python.txt

@@ -31,6 +31,7 @@ ALE will look for configuration files with the following filenames. >
   pycodestyle.cfg
   flake8.cfg
   .flake8rc
+  pylama.ini
   Pipfile
   Pipfile.lock
 <
@@ -449,6 +450,60 @@ g:ale_python_pyflakes_auto_pipenv           *g:ale_python_pyflakes_auto_pipenv*
   if true. This is overridden by a manually-set executable.
 
 
+===============================================================================
+pylama                                                      *ale-python-pylama*
+
+g:ale_python_pylama_change_directory     *g:ale_python_pylama_change_directory*
+                                         *b:ale_python_pylama_change_directory*
+  Type: |Number|
+  Default: `1`
+
+  If set to `1`, `pylama` will be run from a detected project root, per
+  |ale-python-root|.  This is useful because `pylama` only searches for
+  configuration files in its current directory and applies file masks using
+  paths relative to its current directory.  This option can be turned off if
+  you want to control the directory in which `pylama` is executed.
+
+
+g:ale_python_pylama_executable                 *g:ale_python_pylama_executable*
+                                               *b:ale_python_pylama_executable*
+  Type: |String|
+  Default: `'pylama'`
+
+  This variable can be changed to modify the executable used for pylama. Set
+  this to `'pipenv'` to invoke `'pipenv` `run` `pylama'`.
+
+
+g:ale_python_pylama_options                       *g:ale_python_pylama_options*
+                                                  *b:ale_python_pylama_options*
+  Type: |String|
+  Default: `''`
+
+  This variable can be changed to add command-line arguments to the pylama
+  invocation.
+
+
+g:ale_python_pylama_use_global                 *g:ale_python_pylama_use_global*
+                                               *b:ale_python_pylama_use_global*
+  Type: |Number|
+  Default: `get(g:, 'ale_use_global_executables', 0)`
+
+  This variable controls whether or not ALE will search for pylama in a
+  virtualenv directory first. If this variable is set to `1`, then ALE will
+  always use |g:ale_python_pylama_executable| for the executable path.
+
+  Both variables can be set with `b:` buffer variables instead.
+
+
+g:ale_python_pylama_auto_pipenv               *g:ale_python_pylama_auto_pipenv*
+                                              *b:ale_python_pylama_auto_pipenv*
+  Type: |Number|
+  Default: `0`
+
+  Detect whether the file is inside a pipenv, and set the executable to `pipenv`
+  if true. This is overridden by a manually-set executable.
+
+
 ===============================================================================
 pylint                                                      *ale-python-pylint*
 

doc/ale.txt

@@ -269,6 +269,7 @@ CONTENTS                                                         *ale-contents*
       pycodestyle.........................|ale-python-pycodestyle|
       pydocstyle..........................|ale-python-pydocstyle|
       pyflakes............................|ale-python-pyflakes|
+      pylama..............................|ale-python-pylama|
       pylint..............................|ale-python-pylint|
       pyls................................|ale-python-pyls|
       pyre................................|ale-python-pyre|

test/command_callback/test_pylama_command_callback.vader

@@ -0,0 +1,85 @@
+Before:
+  call ale#assert#SetUpLinterTest('python', 'pylama')
+  call ale#test#SetFilename('test.py')
+
+  let b:bin_dir = has('win32') ? 'Scripts' : 'bin'
+  let b:command_tail = ' %t'
+
+After:
+  unlet! b:bin_dir
+  unlet! b:executable
+  unlet! b:command_tail
+
+  call ale#assert#TearDownLinterTest()
+
+Execute(The pylama command callback should return a default):
+  AssertLinter 'pylama',
+  \ ale#path#BufferCdString(bufnr(''))
+  \   . ale#Escape('pylama') . b:command_tail
+
+Execute(The option for disabling changing directories should work):
+  let g:ale_python_pylama_change_directory = 0
+
+  AssertLinter 'pylama', ale#Escape('pylama') . b:command_tail
+
+Execute(The pylama executable should be configurable, and escaped properly):
+  let g:ale_python_pylama_executable = 'executable with spaces'
+
+  AssertLinter 'executable with spaces',
+  \ ale#path#BufferCdString(bufnr(''))
+  \   . ale#Escape('executable with spaces') . b:command_tail
+
+Execute(The pylama command callback should let you set options):
+  let g:ale_python_pylama_options = '--some-option'
+
+  AssertLinter 'pylama',
+  \ ale#path#BufferCdString(bufnr(''))
+  \   . ale#Escape('pylama') . ' --some-option' . b:command_tail
+
+Execute(The pylama command callback should switch directories to the detected project root):
+  silent execute 'file ' . fnameescape(g:dir . '/python_paths/no_virtualenv/subdir/foo/bar.py')
+
+  AssertLinter 'pylama',
+  \ ale#path#CdString(ale#path#Simplify(g:dir . '/python_paths/no_virtualenv/subdir'))
+  \   . ale#Escape('pylama') . b:command_tail
+
+Execute(The pylama command callback shouldn't detect virtualenv directories where they don't exist):
+  silent execute 'file ' . fnameescape(g:dir . '/python_paths/no_virtualenv/subdir/foo/bar.py')
+
+  AssertLinter 'pylama',
+  \ ale#path#CdString(ale#path#Simplify(g:dir . '/python_paths/no_virtualenv/subdir'))
+  \   . ale#Escape('pylama') . b:command_tail
+
+Execute(The pylama command callback should detect virtualenv directories and switch to the project root):
+  silent execute 'file ' . fnameescape(g:dir . '/python_paths/with_virtualenv/subdir/foo/bar.py')
+
+  let b:executable = ale#path#Simplify(
+  \ g:dir . '/python_paths/with_virtualenv/env/' . b:bin_dir . '/pylama'
+  \)
+
+  AssertLinter b:executable,
+  \ ale#path#CdString(ale#path#Simplify(g:dir . '/python_paths/with_virtualenv/subdir'))
+  \   . ale#Escape(b:executable) . b:command_tail
+
+Execute(You should able able to use the global pylama instead):
+  silent execute 'file ' . fnameescape(g:dir . '/python_paths/with_virtualenv/subdir/foo/bar.py')
+  let g:ale_python_pylama_use_global = 1
+
+  AssertLinter 'pylama',
+  \ ale#path#CdString(ale#path#Simplify(g:dir . '/python_paths/with_virtualenv/subdir'))
+  \   . ale#Escape('pylama') . b:command_tail
+
+Execute(Setting executable to 'pipenv' appends 'run pylama'):
+  let g:ale_python_pylama_executable = 'path/to/pipenv'
+
+  AssertLinter 'path/to/pipenv',
+  \ ale#path#BufferCdString(bufnr(''))
+  \   . ale#Escape('path/to/pipenv') . ' run pylama' . b:command_tail
+
+Execute(Pipenv is detected when python_pylama_auto_pipenv is set):
+  let g:ale_python_pylama_auto_pipenv = 1
+  call ale#test#SetFilename('/testplugin/test/python_fixtures/pipenv/whatever.py')
+
+  AssertLinter 'pipenv',
+  \ ale#path#BufferCdString(bufnr(''))
+  \   . ale#Escape('pipenv') . ' run pylama' . b:command_tail

test/handler/test_flake8_handler.vader

@@ -113,7 +113,7 @@ Execute(The flake8 handler should handle stack traces):
   \ [
   \   {
   \     'lnum': 1,
-  \     'text': 'An exception was thrown. See :ALEDetail',
+  \     'text': 'ImportError: No module named parser (See :ALEDetail)',
   \     'detail': join([
   \       'Traceback (most recent call last):',
   \       '  File "/usr/local/bin/flake8", line 7, in <module>',

test/handler/test_pylama_handler.vader

@@ -0,0 +1,212 @@
+Before:
+  Save g:ale_warn_about_trailing_whitespace
+
+  let g:ale_warn_about_trailing_whitespace = 1
+
+  runtime ale_linters/python/pylama.vim
+
+After:
+  Restore
+
+  call ale#linter#Reset()
+
+  silent file something_else.py
+
+Execute(The pylama handler should handle no messages):
+  AssertEqual [], ale_linters#python#pylama#Handle(bufnr(''), [])
+
+Execute(The pylama handler should handle basic warnings and syntax errors):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 8,
+  \     'col': 1,
+  \     'code': 'W0611',
+  \     'type': 'W',
+  \     'sub_type': '',
+  \     'text': '''foo'' imported but unused [pyflakes]',
+  \   },
+  \   {
+  \     'lnum': 8,
+  \     'col': 0,
+  \     'code': 'E0401',
+  \     'type': 'E',
+  \     'sub_type': '',
+  \     'text': 'Unable to import ''foo'' [pylint]',
+  \   },
+  \   {
+  \     'lnum': 10,
+  \     'col': 1,
+  \     'code': 'E302',
+  \     'type': 'E',
+  \     'sub_type': '',
+  \     'text': 'expected 2 blank lines, found 1 [pycodestyle]',
+  \   },
+  \   {
+  \     'lnum': 11,
+  \     'col': 1,
+  \     'code': 'D401',
+  \     'type': 'W',
+  \     'sub_type': 'style',
+  \     'text': 'First line should be in imperative mood (''Get'', not ''Gets'') [pydocstyle]',
+  \   },
+  \   {
+  \     'lnum': 15,
+  \     'col': 81,
+  \     'code': 'E501',
+  \     'type': 'E',
+  \     'sub_type': '',
+  \     'text': 'line too long (96 > 80 characters) [pycodestyle]',
+  \   },
+  \   {
+  \     'lnum': 16,
+  \     'col': 1,
+  \     'code': 'D203',
+  \     'type': 'W',
+  \     'sub_type': 'style',
+  \     'text': '1 blank line required before class docstring (found 0) [pydocstyle]',
+  \   },
+  \   {
+  \     'lnum': 18,
+  \     'col': 1,
+  \     'code': 'D107',
+  \     'type': 'W',
+  \     'sub_type': 'style',
+  \     'text': 'Missing docstring in __init__ [pydocstyle]',
+  \   },
+  \   {
+  \     'lnum': 20,
+  \     'col': 0,
+  \     'code': 'C4001',
+  \     'type': 'W',
+  \     'sub_type': 'style',
+  \     'text': 'Invalid string quote ", should be '' [pylint]',
+  \   },
+  \ ],
+  \ ale_linters#python#pylama#Handle(bufnr(''), [
+  \   'No config file found, using default configuration',
+  \   'index.py:8:1: W0611 ''foo'' imported but unused [pyflakes]',
+  \   'index.py:8:0: E0401 Unable to import ''foo'' [pylint]',
+  \   'index.py:10:1: E302 expected 2 blank lines, found 1 [pycodestyle]',
+  \   'index.py:11:1: D401 First line should be in imperative mood (''Get'', not ''Gets'') [pydocstyle]',
+  \   'index.py:15:81: E501 line too long (96 > 80 characters) [pycodestyle]',
+  \   'index.py:16:1: D203 1 blank line required before class docstring (found 0) [pydocstyle]',
+  \   'index.py:18:1: D107 Missing docstring in __init__ [pydocstyle]',
+  \   'index.py:20:0: C4001 Invalid string quote ", should be '' [pylint]',
+  \ ])
+
+Execute(The pylama handler should handle tracebacks with parsable messages):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 1,
+  \     'text': 'ParseError: Cannot parse file. (See :ALEDetail)',
+  \     'detail': join([
+  \       'Traceback (most recent call last):',
+  \       '  File "/usr/local/lib/python2.7/site-packages/pylama/core.py", line 66, in run',
+  \       '    path, code=code, ignore=ignore, select=select, params=lparams)',
+  \       '  File "/usr/local/lib/python2.7/site-packages/pylama/lint/pylama_pydocstyle.py", line 37, in run',
+  \       '    } for e in PyDocChecker().check_source(*check_source_args)]',
+  \       '  File "/usr/local/lib/python2.7/site-packages/pydocstyle/checker.py", line 64, in check_source',
+  \       '    module = parse(StringIO(source), filename)',
+  \       '  File "/usr/local/lib/python2.7/site-packages/pydocstyle/parser.py", line 340, in __call__',
+  \       '    return self.parse(*args, **kwargs)',
+  \       '  File "/usr/local/lib/python2.7/site-packages/pydocstyle/parser.py", line 328, in parse',
+  \       '    six.raise_from(ParseError(), error)',
+  \       '  File "/usr/local/lib/python2.7/site-packages/six.py", line 737, in raise_from',
+  \       '    raise value',
+  \       'ParseError: Cannot parse file.',
+  \     ], "\n"),
+  \   },
+  \   {
+  \     'lnum': 11,
+  \     'col': 1,
+  \     'code': 'E302',
+  \     'type': 'E',
+  \     'sub_type': '',
+  \     'text': 'expected 2 blank lines, found 1 [pycodestyle]',
+  \   },
+  \   {
+  \     'lnum': 16,
+  \     'col': 81,
+  \     'code': 'E501',
+  \     'type': 'E',
+  \     'sub_type': '',
+  \     'text': 'line too long (96 > 80 characters) [pycodestyle]',
+  \   },
+  \ ],
+  \ ale_linters#python#pylama#Handle(bufnr(''), [
+  \   'Traceback (most recent call last):',
+  \   '  File "/usr/local/lib/python2.7/site-packages/pylama/core.py", line 66, in run',
+  \   '    path, code=code, ignore=ignore, select=select, params=lparams)',
+  \   '  File "/usr/local/lib/python2.7/site-packages/pylama/lint/pylama_pydocstyle.py", line 37, in run',
+  \   '    } for e in PyDocChecker().check_source(*check_source_args)]',
+  \   '  File "/usr/local/lib/python2.7/site-packages/pydocstyle/checker.py", line 64, in check_source',
+  \   '    module = parse(StringIO(source), filename)',
+  \   '  File "/usr/local/lib/python2.7/site-packages/pydocstyle/parser.py", line 340, in __call__',
+  \   '    return self.parse(*args, **kwargs)',
+  \   '  File "/usr/local/lib/python2.7/site-packages/pydocstyle/parser.py", line 328, in parse',
+  \   '    six.raise_from(ParseError(), error)',
+  \   '  File "/usr/local/lib/python2.7/site-packages/six.py", line 737, in raise_from',
+  \   '    raise value',
+  \   'ParseError: Cannot parse file.',
+  \   '',
+  \   'index.py:11:1: E302 expected 2 blank lines, found 1 [pycodestyle]',
+  \   'index.py:16:81: E501 line too long (96 > 80 characters) [pycodestyle]',
+  \ ])
+
+" Note: This is probably a bug, since all pylama plugins produce codes, but
+" should be handled for compatibility.
+" Note: The pylama isort plugin is distributed in the isort package.
+Execute(The pylama handler should handle messages without codes):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 0,
+  \     'col': 0,
+  \     'code': '',
+  \     'type': 'W',
+  \     'sub_type': '',
+  \     'text': 'Incorrectly sorted imports. [isort]'
+  \   },
+  \ ],
+  \ ale_linters#python#pylama#Handle(bufnr(''), [
+  \   'index.py:0:0: Incorrectly sorted imports. [isort]',
+  \ ])
+
+" Note: This is a pylama bug, but should be handled for compatibility.
+" See https://github.com/klen/pylama/pull/146
+Execute(The pylama handler should handle message codes followed by a colon):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 31,
+  \     'col': 1,
+  \     'code': 'E800',
+  \     'type': 'E',
+  \     'sub_type': '',
+  \     'text': 'Found commented out code: # needs_sphinx = ''1.0'' [eradicate]',
+  \   },
+  \ ],
+  \ ale_linters#python#pylama#Handle(bufnr(''), [
+  \   'index.py:31:1: E800: Found commented out code: # needs_sphinx = ''1.0'' [eradicate]',
+  \ ])
+
+" The directory created for %t may not comply with pylint module name config.
+" This should not be reported to users.
+Execute(The pylama handler should ignore C0103 from temp dir, not others):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 29,
+  \     'col': 0,
+  \     'code': 'C0103',
+  \     'type': 'W',
+  \     'sub_type': 'style',
+  \     'text': 'Constant name "badname" doesn''t conform to UPPER_CASE naming style [pylint]',
+  \   },
+  \ ],
+  \ ale_linters#python#pylama#Handle(bufnr(''), [
+  \   '../../../../tmp/vmynR33/456/__init__.py:1:0: C0103 Module name "456" doesn''t conform to snake_case naming style [pylint]',
+  \   '../../../../tmp/vmynR33/456/__init__.py:29:0: C0103 Constant name "badname" doesn''t conform to UPPER_CASE naming style [pylint]',
+  \ ])

test/handler/test_vulture_handler.vader

@@ -70,7 +70,7 @@ Execute(Vulture exception should be handled):
   \ [
   \   {
   \     'lnum': 1,
-  \     'text': 'An exception was thrown. See :ALEDetail',
+  \     'text': 'BaddestException: Everything gone wrong (See :ALEDetail)',
   \     'detail': join([
   \       'Traceback (most recent call last):',
   \       '  File "/usr/lib/python3.6/site-packages/vulture/__init__.py", line 13, in <module>',

test/test_python_traceback.vader

@@ -0,0 +1,79 @@
+Execute(ale#python#HandleTraceback returns empty List for empty lines):
+  AssertEqual
+  \  [],
+  \  ale#python#HandleTraceback([], 10)
+
+Execute(ale#python#HandleTraceback returns traceback, when present):
+  AssertEqual
+  \  [{
+  \    'lnum': 1,
+  \    'text': 'Exception: Example error (See :ALEDetail)',
+  \    'detail': join([
+  \      'Traceback (most recent call last):',
+  \      '  File "./example.py", line 5, in <module>',
+  \      '    raise Exception(''Example message'')',
+  \      'Exception: Example error',
+  \    ], "\n"),
+  \  }],
+  \  ale#python#HandleTraceback([
+  \    'Traceback (most recent call last):',
+  \    '  File "./example.py", line 5, in <module>',
+  \    '    raise Exception(''Example message'')',
+  \    'Exception: Example error',
+  \  ], 1)
+
+" SyntaxError has extra output lines about the source
+Execute(ale#python#HandleTraceback returns SyntaxError traceback):
+  AssertEqual
+  \  [{
+  \    'lnum': 1,
+  \    'text': 'SyntaxError: invalid syntax (See :ALEDetail)',
+  \    'detail': join([
+  \      'Traceback (most recent call last):',
+  \      '  File "<string>", line 1, in <module>',
+  \      '  File "example.py", line 5',
+  \      '    +',
+  \      '    ^',
+  \      'SyntaxError: invalid syntax',
+  \    ], "\n"),
+  \  }],
+  \  ale#python#HandleTraceback([
+  \    'Traceback (most recent call last):',
+  \    '  File "<string>", line 1, in <module>',
+  \    '  File "example.py", line 5',
+  \    '    +',
+  \    '    ^',
+  \    'SyntaxError: invalid syntax',
+  \  ], 1)
+
+Execute(ale#python#HandleTraceback ignores traceback after line limit):
+  AssertEqual
+  \  [],
+  \  ale#python#HandleTraceback([
+  \    '',
+  \    'Traceback (most recent call last):',
+  \    '  File "./example.py", line 5, in <module>',
+  \    '    raise Exception(''Example message'')',
+  \    'Exception: Example error',
+  \  ], 1)
+
+Execute(ale#python#HandleTraceback doesn't include later lines in detail):
+  AssertEqual
+  \  [{
+  \    'lnum': 1,
+  \    'text': 'Exception: Example error (See :ALEDetail)',
+  \    'detail': join([
+  \      'Traceback (most recent call last):',
+  \      '  File "./example.py", line 5, in <module>',
+  \      '    raise Exception(''Example message'')',
+  \      'Exception: Example error',
+  \    ], "\n"),
+  \  }],
+  \  ale#python#HandleTraceback([
+  \    'Traceback (most recent call last):',
+  \    '  File "./example.py", line 5, in <module>',
+  \    '    raise Exception(''Example message'')',
+  \    'Exception: Example error',
+  \    'file:1:2: Style issue',
+  \    'file:3:4: Non-style issue',
+  \  ], 1)