[ci skip] Add one more example to routing testing, and highlight association

name keywords

guides/source/testing.md

@@ -82,7 +82,7 @@ Each fixture is given a name followed by an indented list of colon-separated key
 
 If you are working with [associations](/association_basics.html), you can simply
 define a reference node between two different fixtures. Here's an example with
-a belongs_to/has_many association:
+a `belongs_to`/`has_many` association:
 
 ```yaml
 # In fixtures/categories.yml
@@ -901,13 +901,17 @@ end
 Testing Routes
 --------------
 
-Like everything else in your Rails application, it is recommended that you test your routes. An example test for a route in the default `show` action of `Articles` controller above should look like:
+Like everything else in your Rails application, it is recommended that you test your routes. Below are example tests for the routes of default `show` and `create` action of `Articles` controller above and it should look like:
 
 ```ruby
 class ArticleRoutesTest < ActionController::TestCase
   test "should route to article" do
     assert_routing '/articles/1', { controller: "articles", action: "show", id: "1" }
   end
+
+  test "should route to create article" do
+    assert_routing({ method: 'post', path: '/articles' }, { controller: "articles", action: "create" })
+  end
 end
 ```