Finished chap3

2020-11-07 15:27:12 +11:00 · 2020-11-07 15:27:12 +11:00 · 9fa1028ce1
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@ -125,8 +125,84 @@ Overall, the traceback can be interpreted as: "when trying to resolve `/`, Djang

 ## 3.6 urls.py

+Django use `urls.py` in each app to map URLs to view functions.

+```python
+urlpatterns = [
+    url(r'^admin/', admin.site.urls),
+]
+```
+
+Note:
+* This book use Django v1.11. So `path` function is not utilized, it's used in v3.x
+
+Explain:
+* `url` start with a regex, which defines which URLs it looks for, and where (function) should these request to send
+* `^$` means empty string
+
+Modifying `superlists.urls` to 
+
+```python
+from django.conf.urls import url
+from lists import views
+
+urlpatterns = [
+    url(r'^$', views.home_page, name='home'),
+]
+```
+
+Generate error as shown
+
+```
+...
+File "/home/jason/HomeWorkstation/SynologyGiteaSpace/python-tdd-book-src/src/superlists/urls.py", line 20, in <module>
+    url(r'^$', views.home_page, name='home'),
+  File "/home/jason/miniconda3/envs/python-tdd-book/lib/python3.6/site-packages/django/conf/urls/__init__.py", line 85, in url
+    raise TypeError('view must be a callable or a list/tuple in the case of include().')
+TypeError: view must be a callable or a list/tuple in the case of include().
+```
+
+Analyzing error message "TypeError: view must be a callable or a list/tuple in the case of include().": unit tests have actually made the link btw the URL "/" and `home_page = None` in `lists/views.py`, and are now complaining that `home_page` view is not callable.
+
+Fix this problem via modifying `lists/views.py`
+
+```python
+def home_page():
+    pass
+```

 ## 3.7 Unit Testing a View

-### 3.7.1 The Unit-Test/Code Cycle
+After creating simple `home_page` empty function. We can create test function in `lists/tests.py`
+
+```python
+  def test_home_page_returns_correct_html(self):
+        request = HttpRequest()
+        response = home_page(request)
+        html = response.content.decode('utf8')
+        self.assertTrue(html.startswith('<html>'))
+        self.assertIn('<title>To-Do list</title>', html)
+        self.assertTrue(html.endswith('</html>'))
+```
+
+Result of `python manager.py test` is: 
+
+```
+line 15, in test_home_page_returns_correct_html
+    response = home_page(request)
+TypeError: home_page() takes 0 positional arguments but 1 was given
+```
+
+### 3.7.1 The Unit-Test/Code Cycle
+
+TDD *unit-test/code cycle*:
+1. In the terminal, run unit tests and see how they fail
+2. In the editor, create minimal code change to fix test failure.
+3. Repeat
+
+Fix the `views.py` to
+
+```python
+def home_page(request):
+    return HttpResponse('<html><title>To-Do list</title></html>')
+```