ImageDimensionBear: Add image dimension bear

Added ImageDimensionBear.py in bears/general, that runs
the gem img_checker to see if images follow given
dimensions by user.
Also added unittest for the bear, ImageDimensionBearTest.py
in tests/general

Closes #1260

Gemfile

@@ -2,6 +2,7 @@ source 'https://rubygems.org'
 ruby '2.2.2'
 
 gem "csvlint"
+gem "img_checker"
 gem "puppet-lint"
 gem "reek"
 gem "rubocop"

bears/general/ImageDimensionBear.py

@@ -0,0 +1,96 @@
+from glob import glob
+import os
+import yaml
+import shutil
+
+from coalib.bears.GlobalBear import GlobalBear
+from coalib.results.Result import Result
+from coalib.results.RESULT_SEVERITY import RESULT_SEVERITY
+from dependency_management.requirements.GemRequirement import GemRequirement
+from dependency_management.requirements.PipRequirement import PipRequirement
+from sarge import run, Capture
+
+
+def check_path(image_file):
+    if (glob(str(image_file)) == []):
+        raise ValueError('Provide a correct path for image')
+    else:
+        return os.path.join('..', str(image_file))
+
+
+def check_width(width):
+    if (int(width) <= 0):
+        raise ValueError('Width has to be greater than 0')
+
+    else:
+        return int(width)
+
+
+def check_height(height):
+    if (int(height) <= 0):
+        raise ValueError('Height has to be greater than 0')
+    else:
+        return int(height)
+
+
+class ImageDimensionBear(GlobalBear):
+    """
+    Checks the dimension of an image us a gem.
+
+    More information is available at <github.com/Abhi2424shek/img_checker>
+    """
+
+    AUTHORS = {'The coala developers'}
+    AUTHORS_EMAILS = {'[email protected]'}
+    REQUIREMENTS = {GemRequirement('img_checker'),
+                    PipRequirement('pyyaml', '3.12')}
+    LICENSE = 'AGPL-3.0'
+    CAN_FIX = {'Image Dimension'}
+
+    @classmethod
+    def check_prerequisites(cls):
+        if shutil.which('img_checker') is None:
+            return 'img_checker is not installed.'
+        return True
+
+    def run(self,
+            image_file: check_path,
+            width: check_width,
+            height: check_height):
+        """
+        This bear ensures that images used in your project are
+        within a fixed dimension.
+
+        WARNING: If your repository has an existing img_config.yml
+        file, please change it since this bear creates a file
+        with that name and removes it in the end.
+
+        :param image_file: The file/directory that bear
+                           will look for images
+        :param width:      The maximum width value allowed
+                           for images
+        :param height:     The maximum height value allowed
+                           for images
+        """
+        # self.warn(warning_message)
+        os.mkdir('temp_dir_for_img_config_file')
+        os.chdir('temp_dir_for_img_config_file')
+        with open('img_config.yml', 'w') as yaml_file:
+            config = [{'directory': image_file,
+                       'width': width,
+                       'height': height}]
+            yaml.dump(config, yaml_file, default_flow_style=False)
+        self.debug(glob(image_file))
+        cmd = 'img_checker'
+        output = run(cmd, stdout=Capture(), stderr=Capture())
+        os.remove('img_config.yml')
+        os.chdir('..')
+        os.rmdir('temp_dir_for_img_config_file')
+        if (output.returncode):
+            lines = output.stdout.text.split('\n')[1:-2]
+            for line in lines:
+                line = line[0:line.index('image')+6] + \
+                                line[line.index('image')+9:]
+                yield Result(origin=self,
+                             message=line,
+                             severity=RESULT_SEVERITY.MAJOR)

test-img/.coafile

@@ -0,0 +1,6 @@
+[Default]
+bears = ImageDimensionBear
+files = .coafile
+image_file = ./test-img/*.*
+width = 240
+height = 240

tests/general/ImageDimensionBearTest.py

@@ -0,0 +1,91 @@
+import unittest
+from unittest.case import skip, skipIf
+from queue import Queue
+import shutil
+
+from bears.general.ImageDimensionBear import *
+from coalib.output.printers.LOG_LEVEL import LOG_LEVEL
+from coalib.settings.Section import Section
+from coalib.settings.Setting import Setting
+from coalib.testing.BearTestHelper import generate_skip_decorator
+
+
+@generate_skip_decorator(ImageDimensionBear)
+class ImageDimensionBearTest(unittest.TestCase):
+    """
+    Runs unittests for ImageDimensionBear
+    """
+
+    def setUp(self):
+        self.section = Section('')
+        self.queue = Queue()
+        self.file_dict = {}
+        self.idb = ImageDimensionBear(None, self.section, self.queue)
+
+    def test_check_width(self):
+        with self.assertRaisesRegexp(ValueError, 'Width'):
+            check_width('-12')
+        self.assertEqual(check_width('120'), 120)
+
+    def test_check_height(self):
+        with self.assertRaisesRegexp(ValueError, 'Height'):
+            check_height('-12')
+        self.assertEqual(check_height('120'), 120)
+
+    def test_check_path(self):
+        with self.assertRaisesRegexp(ValueError, 'Provide'):
+            check_path('test-image/')
+        self.assertEqual(check_path('test-img/'), '../test-img/')
+
+    def test_check_prerequisites(self):
+        _shutil_which = shutil.which
+        try:
+            shutil.which = lambda *args, **kwargs: None
+            self.assertEqual(ImageDimensionBear.check_prerequisites(),
+                             'img_checker is not installed.')
+
+            shutil.which = lambda *args, **kwargs: 'path/to/bundle'
+            self.assertTrue(ImageDimensionBear.check_prerequisites())
+        finally:
+            shutil.which = _shutil_which
+
+    def test_run_with_png(self):
+        path = os.path.join('..', 'test-img', '*.png')
+        message = ('The image test-img/img.png is larger'
+                   ' than 240px x 240px [w x h]')
+        result = next(self.idb.run(
+                       image_file=path,
+                       width=240,
+                       height=240))
+        self.assertEqual(message,
+                         result.message)
+
+    def test_run_with_jpg(self):
+        path = os.path.join('..', 'test-img', '*.jpg')
+        self.assertEqual([],
+                         list(self.idb.run(
+                               image_file=path,
+                               width=240,
+                               height=240)))
+
+    def test_run_with_jpg_fail(self):
+        path = os.path.join('..', 'test-img', '*.jpg')
+        message = ('The image test-img/images.jpg is larger'
+                   ' than 50px x 50px [w x h]')
+        result = next(self.idb.run(
+                       image_file=path,
+                       width=50,
+                       height=50))
+        self.assertEqual(message,
+                         result.message)
+
+    def test_run_with_both(self):
+        path = os.path.join('..', 'test-img', '*.*')
+        message = ('\w* \w+-\w+\/\w+\.\w+ is larger'
+                   ' than 50px x 50px \[w x h]')
+        output = str(list(self.idb.run(
+                       image_file=path,
+                       width=50,
+                       height=50)))
+        self.assertRegex(output,
+                         message)