Add :DESC section to test case description

testing.html

@@ -8,8 +8,6 @@ title: Test Cases
 The boxes sources have a low-tech test suite in the [test](https://github.com/{{ site.github }}/tree/master/test){:target="_blank"} subdirectory.
 Travis CI will execute it in order to make sure that a change did not break the program.
 
-Currently, the test suite could use more test cases, so any help with growing the number of tests is highly appreciated.
-
 
 <a class="bxOffsetAnchor" name="invocation"></a>
 
@@ -28,10 +26,15 @@ Each test case is a single file within the *test* subdirectory. It must follow t
 
     nnn_description.txt
 
-where `nnn` is a three-digit number which uniquely identifies the test case. `description` is any short text that describes what the test case does. It must not contain spaces; use underscores instead. The file extension is always `.txt`.
+where `nnn` is a three-digit number which uniquely identifies the test case. `description` is any short text that
+describes what the test case does. It must not contain spaces; use underscores instead. The file extension is always
+`.txt`.
 
 A test case that tests a **successful** invocation of boxes looks like this:
 
+    :DESC
+	Tests invoking boxes with a fixed result box size.
+    
     :ARGS
     -s 10x4
     :INPUT
@@ -44,10 +47,15 @@ A test case that tests a **successful** invocation of boxes looks like this:
     /********/
     :EOF
 
-Sections may be empty, e.g. if there are no arguments or there is no input.
+Sections may be empty, e.g. if there are no arguments or there is no input. The `:DESC` section is optional, so it is
+valid if the test case starts with an `:ARGS` section. The order of sections is fixed.
 
 A test case that makes sure boxes **fails** under certain conditions looks like this:
 
+    :DESC
+	Tests that the right error message is shown when the boxes
+	config file cannot be found.
+    
     :ARGS
     -f nonexistent
     :INPUT
@@ -56,6 +64,11 @@ A test case that makes sure boxes **fails** under certain conditions looks like
     boxes: Couldn't open config file 'nonexistent' for input.
     :EOF
 
-Note that you write `:EXPECTED-ERROR` instead of just `:EXPECTED`, and the expected return code is given after a space (in this example, it is `1`).
+Note that you write `:EXPECTED-ERROR` instead of just `:EXPECTED`, and the expected return code is given after a space
+(in this example, it is `1`).
 
-The `:OUTPUT-FILTER` section can be used to give a *sed* script which is run on the actual output before comparing it to the expected output ([example](https://github.com/{{ site.github }}/blob/master/test/065_size_missing_argument.txt){:target="_blank"}). This way, differences in output that occur because of platform differences can be filtered out. The general advice is to leave this section empty unless you are facing a situation where there is no other solution.
+The `:OUTPUT-FILTER` section can be used to give a *sed* script which is run on the actual output before comparing it
+to the expected output
+([example](https://github.com/{{ site.github }}/blob/master/test/065_size_missing_argument.txt){:target="_blank"}).
+This way, differences in output that occur because of platform differences can be filtered out. The general advice is
+to leave this section empty unless you are facing a situation where there is no other solution.