Refactor. Add test that was previously not-covered.

diff_cover/tests/test_violations_reporter.py

@@ -983,6 +983,10 @@ def setUp(self):
         # Mock patch the installation of jshint
         _mock_command_simple = patch.object(JsHintQualityReporter, '_run_command_simple').start()
         _mock_command_simple.return_value = 0
+        self._mock_communicate = patch.object(subprocess, 'Popen').start()
+        self.subproc_mock = MagicMock()
+        self.subproc_mock.returncode = 0
+
 
     def tearDown(self):
         """
@@ -996,15 +1000,13 @@ def test_quality(self):
         """
 
         # Patch the output of `jshint`
-        _mock_popen_init = patch.object(Popen, '__init__').start()
-        _mock_popen_init.return_value = None
-        _mock_communicate = patch.object(Popen, 'communicate').start()
         return_string = '\n' + dedent("""
                 ../test_file.js: line 3, col 9, Missing "use strict" statement.
                 ../test_file.js: line 10, col 17, '$hi' is defined but never used.
             """).strip() + '\n'
-        _mock_communicate.return_value = (
+        self.subproc_mock.communicate.return_value = (
             (return_string.encode('utf-8'), b''))
+        self._mock_communicate.return_value = self.subproc_mock
 
         # Parse the report
         quality = JsHintQualityReporter('jshint', [])
@@ -1027,10 +1029,8 @@ def test_quality(self):
     def test_no_quality_issues_newline(self):
 
         # Patch the output of `jshint`
-        _mock_popen_init = patch.object(Popen, '__init__').start()
-        _mock_popen_init.return_value = None
-        _mock_communicate = patch.object(Popen, 'communicate').start()
-        _mock_communicate.return_value = (b'\n', b'')
+        self.subproc_mock.communicate.return_value = (b'\n', b'')
+        self._mock_communicate.return_value = self.subproc_mock
 
         # Parse the report
         quality = JsHintQualityReporter('jshint', [])
@@ -1039,23 +1039,21 @@ def test_no_quality_issues_newline(self):
     def test_no_quality_issues_emptystring(self):
 
         # Patch the output of `jshint`
-        _mock_popen_init = patch.object(Popen, '__init__').start()
-        _mock_popen_init.return_value = None
-        _mock_communicate = patch.object(Popen, 'communicate').start()
-        _mock_communicate.return_value = (b'', b'')
+        self.subproc_mock.communicate.return_value = (b'', b'')
+        self._mock_communicate.return_value = self.subproc_mock
 
         # Parse the report
         quality = JsHintQualityReporter('jshint', [])
         self.assertEqual([], quality.violations('file1.js'))
 
     def test_quality_error(self):
 
+        # Override the subprocess return code to a failure
+        self.subproc_mock.returncode = 1
+
         # Patch the output of `jshint`
-        _mock_communicate = patch.object(subprocess, 'Popen').start()
-        subproc_mock = MagicMock()
-        subproc_mock.returncode = 1
-        subproc_mock.communicate.return_value = (b"", 'whoops Ƕئ'.encode('utf-8'))
-        _mock_communicate.return_value = subproc_mock
+        self.subproc_mock.communicate.return_value = (b"", 'whoops Ƕئ'.encode('utf-8'))
+        self._mock_communicate.return_value = self.subproc_mock
 
         # Parse the report
         quality = JsHintQualityReporter('jshint', [])
@@ -1121,8 +1119,19 @@ def test_quality_pregenerated_report(self):
         for expected in expected_violations:
             self.assertIn(expected, actual_violations)
 
+    def test_not_installed(self):
+        """
+        If jshint is not available via commandline, it should raise an EnvironmentError
+        """
+        _mock_command_simple = patch.object(JsHintQualityReporter, '_run_command_simple').start()
+        _mock_command_simple.return_value = 1
+        with self.assertRaises(EnvironmentError):
+            JsHintQualityReporter('jshint', [])
 
 class SubprocessErrorTestCase(unittest.TestCase):
+    """
+    Error in subprocess call(s)
+    """
     def setUp(self):
         # when you create a new subprocess.Popen() object and call .communicate()
         # on it, raise an OSError