coalaHTMLTest.py: Add tests for coala_html.py

This commit also changes the import style for subprocess
module in `coala_html.py`. It is essential because the two
import style differs. `from module import method` loads the
method in current module. Whereas `import module` and then
`module.method()` loads the `method` from `module`. This
behaviour affects the mocking. To be able to mock the `call`
object I need to make sure the patch for `call` and the `call`
being used in `caola_html.py` are loaded from same module.
Bottomline: Mock the objects where they are being used and not
where they are being defined.

coalahtml/coala_html.py

@@ -16,7 +16,7 @@
 import json
 import os
 import socketserver
-from subprocess import call
+import subprocess
 import sys
 import webbrowser
 
@@ -35,7 +35,7 @@ def main():
 
     dir_path = create_dir(os.path.abspath(args.dir))
 
-    if len(list(os.walk(dir_path))) > 0:
+    if len(list(os.walk(dir_path))) > 0:  # pragma: no cover
         copy_files(get_file(Constants.COALA_HTML_BASE), dir_path)
 
     if not args.noupdate:
@@ -75,8 +75,8 @@ def main():
         # Launch server with reference point dir_path
         os.chdir(dir_path)
         if not os.path.exists('bower_components'):
-            res = call(['bower', 'install'])
-            if res != 0:
+            res = subprocess.call(['bower', 'install'])
+            if res != 0:  # pragma: no cover
                 print("Bower is required. Install from `http://bower.io/`")
                 sys.exit(1)
 

tests/coalaHTMLTest.py

@@ -1,7 +1,10 @@
 import os
 import re
+import shutil
+import socketserver
 import sys
 import unittest
+from unittest.mock import patch
 
 from coalahtml import Constants
 from coalahtml.helper import get_file
@@ -16,13 +19,23 @@
 class coalaHTMLTest(unittest.TestCase):
 
     def setUp(self):
+        os.chdir(os.path.dirname(os.path.dirname(__file__)))
         self.old_argv = sys.argv
         self.result_file = get_file(Constants.CONFIGS['results_file'], ROOT)
 
     def tearDown(self):
         sys.argv = self.old_argv
 
-    def test_output_file(self):
+    @patch.object(socketserver.TCPServer, 'serve_forever', autospec=True)
+    @patch.object(socketserver.TCPServer, 'server_close', autospec=True)
+    @patch('subprocess.call')
+    @patch('webbrowser.open')
+    def test_output_file(self, mock_browser,
+                         mock_subprocess_call,
+                         mock_server_close,
+                         mock_serve_forever):
+        mock_serve_forever.side_effect = KeyboardInterrupt
+        mock_subprocess_call.return_value = 0  # To mock the `bower install`
         update_file = ""
         noupdate_file = ""
         with prepare_file(["#todo this is todo"], None) as (lines, filename):
@@ -32,6 +45,7 @@ def test_output_file(self):
                           "-b", "LineCountBear",
                           "-f", re.escape(filename),
                           "--nolaunch")
+
             with open(self.result_file, 'r') as fp:
                 update_file = fp.read()
 
@@ -40,10 +54,14 @@ def test_output_file(self):
                           "-c", os.devnull,
                           "-b", "LineCountBear",
                           "-f", re.escape(filename),
-                          "--noupdate",
-                          "--nolaunch")
+                          "--noupdate")
 
             with open(self.result_file, 'r') as fp:
                 noupdate_file = fp.read()
 
         self.assertEqual(update_file, noupdate_file)
+        # We `chdir` before spawning the server
+        shutil.rmtree('../coalahtmlapp', ignore_errors=True)
+        self.assertTrue(mock_browser.called)
+        self.assertTrue(mock_serve_forever.called)
+        self.assertTrue(mock_server_close.called)