ImageDimensionBear: Add image dimension bear

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

Gemfile

@@ -7,3 +7,5 @@ gem 'scss_lint', require: false# require flag is necessary https://github.com/br
 gem "reek"
 gem "puppet-lint"
 gem "csvlint"
+gem "img_checker"
+gem "fastimage"

bears/general/ImageDimensionBear.py

@@ -0,0 +1,53 @@
+import os
+import yaml
+
+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
+
+
+class ImageDimensionBear(GlobalBear):
+    """
+    Checks the dimension of an image.
+
+    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'}
+
+    def run(self,
+            image_config):
+
+        with open('img_config.yml', 'w') as yaml_file:
+            for each in image_config:
+                each = each.split(' ')
+                config = [{'directory': each[0],
+                           'width': int(each[1]),
+                           'height': int(each[2])}]
+                yaml.dump(config, yaml_file, default_flow_style=False)
+
+        cmd = 'ruby -r "img_checker.rb" -e '
+        cmd += '"ImgChecker.new.initialize img_config.yml"'
+        output = run(cmd, stdout=Capture(), stderr=Capture())
+        if (output.returncode):
+            lines = output.stdout.text.split('\n')[1:-2]
+            for line in lines:
+                if '.png' in line:
+                    fileName = line[10:line.index('.png')+4]
+                elif '.jpg' in line:
+                    fileName = line[10:line.index('.jpg')+4]
+
+                yield Result.from_values(origin=self,
+                                         message=line,
+                                         file=fileName,
+                                         severity=RESULT_SEVERITY.NORMAL)
+
+        os.remove('img_config.yml')

tests/general/ImageDimensionBearTest.py

@@ -0,0 +1,47 @@
+import unittest
+from queue import Queue
+
+from bears.general.ImageDimensionBear import ImageDimensionBear
+from coalib.settings.Section import Section
+
+
+class ImageDimensionBearTest(unittest.TestCase):
+    """
+    Runs unittests for ImageDimensionBear
+    """
+
+    def setUp(self):
+        self.section = Section('name')
+        self.queue = Queue()
+        self.file_dict = {}
+        self.idb = ImageDimensionBear(self.file_dict, self.section, self.queue)
+
+    def test_run_with_png(self):
+        message = "message='The image ./test-img/img.png is larger"
+        message += " than 240px x 240px [w x h]'"
+        self.assertIn(message,
+                      str(list(self.idb.run(
+                               image_config=['./test-img/*.png 240 240']))))
+
+    def test_run_with_jpg(self):
+        self.assertEqual('[]',
+                         str(list(self.idb.run(
+                                  image_config=['./test-img/*.jpg 240 240']))))
+
+    def test_run_with_jpg_fail(self):
+        message = "message='The image ./test-img/images.jpg is larger"
+        message += " than 50px x 50px [w x h]'"
+        self.assertIn(message,
+                      str(list(self.idb.run(
+                               image_config=['./test-img/*.jpg 50 50']))))
+
+    def test_run_with_both(self):
+        message_png = "message='The image ./test-img/img.png is larger"
+        message_png += " than 50px x 50px [w x h]'"
+        message_jpg = "message='The image ./test-img/images.jpg is larger"
+        message_jpg += " than 50px x 50px [w x h]'"
+        output = str(list(self.idb.run(image_config=['./test-img/*.* 50 50'])))
+        self.assertIn(message_png,
+                      output)
+        self.assertIn(message_jpg,
+                      output)