 
       # File: assertion_test.exs
 
-      # 1) Start ExUnit. You can pass some options
-      #    (see `configure/1` for the list of options)
+      # 1) Start ExUnit.
       ExUnit.start
 
-      # 2) Create a new test module (test case) and use ExUnit.Case
+      # 2) Create a new test module (test case) and use `ExUnit.Case`.
       defmodule AssertionTest do
-        # 3) Notice we pass async: true, this runs the test case
+        # 3) Notice we pass `async: true`, this runs the test case
         #    concurrently with other test cases
         use ExUnit.Case, async: true
 
         # 4) A test is a function whose name starts with
-        #    test and receives a context
+        #    `test` and receives a context.
         def test_always_pass(_) do
           assert true
         end
 
-        # 5) It is recommended to use the "test" macro instead of def
+        # 5) Use the `test` macro instead of `def` for clarity.
         test "the truth" do
           assert true
         end
       end
 
-  To run the test above, all you need to do is to run the file
-  using `elixir` from the command line. Assuming you named your file
+  To run the tests above, run the file
+  using `elixir` from the command line. Assuming you named the file
   `assertion_test.exs`, you can run it as:
 
       bin/elixir assertion_test.exs
 
-  ## Case, callbacks and assertions
+  ## Case, Callbacks and Assertions
 
-  See `ExUnit.Case` and `ExUnit.Callbacks` for more information about
+  See [`ExUnit.Case`](ExUnit.Case.html) and [`ExUnit.Callbacks`](ExUnit.Callbacks.html) for more information about
   defining test cases.
 
-  The `ExUnit.Assertions` module contains a set of macros to easily
+  The [`ExUnit.Assertions`](ExUnit.Assertions.html) module contains a set of macros to easily
   generate assertions with appropriate error messages.
 
   ## Integration with Mix
 
   Mix is the project management and build tool for Elixir. Invoking `mix test`
-  from the command line will run tests in each file matching the pattern
+  from the command line will run the tests in each file matching the pattern
   `*_test.exs` found in the `test` directory of your project.
 
-  By convention, you could also create a `test_helper.exs` file inside the
+  You must create a `test_helper.exs` file inside the
   `test` directory and put the code common to all tests there.
 
   The minimum example of a `test_helper.exs` file would be:

  ExUnit supports the following options:

  * `:color` - When color should be used by specific formatters.
               Defaults to the result of `IO.ANSI.terminal?`;

  * `:formatter` - The formatter that will print results.
                   Defaults to `ExUnit.CLIFormatter`;

      # test/test_helper.exs
      ExUnit.start

  Mix will load the `test_helper.exs` file before executing the tests. 
  It is not necessary to `require` the `test_helper.exs` file in your test files.
  See [`Mix.Tasks.Test`](Mix.Tasks.Test.html) for more information.

  """

