natural_language: Add SpellCheckBear

This bear uses ``scspell`` to check for spelling mistakes.

Closes #629

bears/natural_language/SpellCheckBear.py

@@ -0,0 +1,24 @@
+from coalib.bearlib.abstractions.Linter import linter
+from coalib.bears.requirements.PipRequirement import PipRequirement
+
+
+@linter(executable='scspell',
+        use_stderr=True,
+        output_format='regex',
+        output_regex=r'(?P<filename>.*):(?P<line>.\d*):\s*(?P<message>.*)')
+class SpellCheckBear:
+    """
+    Lints files to check for incorrect spellings using ``scspell``.
+
+    See <https://pypi.python.org/pypi/scspell> for more information.
+    """
+    LANGUAGES = {"Natural Language"}
+    REQUIREMENTS = {PipRequirement('scspell3k', '2.0')}
+    AUTHORS = {'The coala developers'}
+    AUTHORS_EMAILS = {'coala-devel@googlegroups.com'}
+    LICENSE = 'AGPL-3.0'
+    CAN_DETECT = {'Spelling'}
+
+    @staticmethod
+    def create_arguments(filename, file, config_file):
+        return '--report-only', filename

requirements.txt

@@ -28,3 +28,4 @@ pyyaml==3.*
 vulture==0.10.*
 nbformat>=4.*
 pyflakes==1.2.*  # Although we don't need this directly, solves a dep conflict
+scspell3k==2.*

tests/natural_language/SpellCheckBearTest.py

@@ -0,0 +1,17 @@
+import platform
+import unittest
+
+from bears.natural_language.SpellCheckBear import SpellCheckBear
+from tests.LocalBearTestHelper import verify_local_bear
+
+good_file = "This is correct spelling."
+
+bad_file = "tihs si surly som incoreclt speling."
+
+
+SpellCheckLintBearTest = unittest.skipIf(
+    platform.system() == "Windows",
+    "SpellCheckBear doesn't work on windows")(
+        verify_local_bear(SpellCheckBear,
+                          valid_files=(good_file,),
+                          invalid_files=(bad_file,)))