added coveralls support and refactored some code

.coveragerc

@@ -0,0 +1,2 @@
+[run]
+omit = tests/*

.travis.yml

@@ -1,6 +1,11 @@
 language: python
-install: true
+install:
+    - pip install pytest-cov
+    - pip install coveralls
 python:
     - "3.3"
     - "2.6"
-script: py.test
+script:
+    - py.test --cov-config .coveragerc --cov=. tests/
+after_success:
+    coveralls

app/hours_calculator.py

@@ -34,10 +34,7 @@ def _calculate_total_minutes_from_string(self, time_string):
 
         time_list = time_string.split(':')
         hours = int(time_list[0])
-        try:
-            minutes = int(time_list[1])
-        except IndexError:
-            minutes = 0
+        minutes = int(time_list[1])
 
         total_minutes = minutes + hours * 60
 
@@ -52,5 +49,4 @@ def _is_valid_format(self, hour):
 if __name__ == '__main__':
     import sys
 
-    calc = HoursCalculator()
-    print(calc.add(*sys.argv[1:]))
+    print(HoursCalculator().add(*sys.argv[1:]))

calculator.py

@@ -10,5 +10,4 @@
 
 class CalculateHoursCommand(sublime_plugin.TextCommand):
     def run(self, edit):
-        command = SublimeCommand()
-        command.calculate_hours(edit, self.view)
+        SublimeCommand().calculate_hours(edit, self.view)

tests/test_hours_calculator.py

@@ -55,6 +55,7 @@ def test_add_single_negative_hour(self):
     def test_add_positive_with_negative_hours(self):
         self.assertEqual("00:10", self.calculator.add("1:10", "-1:00"))
         self.assertEqual("00:00", self.calculator.add("1:10", "-1:10"))
+        self.assertEqual("-00:05", self.calculator.add("1:10", "-1:15"))
         self.assertEqual("00:05", self.calculator.add("2:10", "-1:65"), 'Negative hour with 65 minutes')
 
     def test_add_multiple_negative_hours(self):