Feature/tweetting fix

.travis.yml

@@ -11,7 +11,10 @@ script: py.test
 before_install:
   - sudo apt-get -y update
   - sudo apt-get install firefox-geckodriver
-  - sudo apt-get install --upgrade chromium-chromedriver
+before_script:
+  - wget https://chromedriver.storage.googleapis.com/83.0.4103.39/chromedriver_linux64.zip
+  - unzip chromedriver_linux64.zip -d /home/travis/virtualenv/python3.7.1/bin/
+  - export CHROME_BIN=chromium-browser
 after_failure: cat test/diffengine.log
 notifications:
   slack:

diffengine/__init__.py

@@ -298,6 +298,18 @@ class Diff(BaseModel):
     emailed = DateTimeField(null=True)
     blogged = DateTimeField(null=True)
 
+    @property
+    def url_changed(self):
+        return self.old.url != self.new.url
+
+    @property
+    def title_changed(self):
+        return self.old.title != self.new.title
+
+    @property
+    def summary_changed(self):
+        return self.old.summary != self.new.summary
+
     @property
     def html_path(self):
         # use prime number to spread across directories

diffengine/twitter.py

@@ -66,7 +66,7 @@ def tweet_diff(self, diff, token=None, lang={}):
 
         # Check if the thread exists
         thread_status_id_str = None
-        if diff.old.entry.tweet_status_id_str is None:
+        if diff.old.entry.tweet_status_id_str == "":
             try:
                 thread_status_id_str = self.create_thread(
                     diff.old.entry, diff.old, token

test_diffengine.py

@@ -423,7 +423,7 @@ def test_create_thread_if_old_entry_has_no_related_tweet(
     ):
 
         entry = MagicMock()
-        type(entry).tweet_status_id_str = PropertyMock(return_value=None)
+        type(entry).tweet_status_id_str = PropertyMock(return_value="")
 
         diff = get_mocked_diff()
         type(diff.old).entry = entry