update pytest readme

Author: ShMcK

README.md

@@ -12,18 +12,27 @@ Install Python
 
 ### Writing Tests
 
-There are two things your tests will need.
+There are two parts your tests will need: a task number and a feedback message.
 
-* a `class Test##` specifying the task number
+##### Task number
 
-      class TestO1:
+Class title specifying the task number: `class Test##`
+
+      class Test01:
+        # tests here
 
       class Test02:
+        # tests here
 
-* a test method providing the feedback message and starting with `test_`
+##### Feedback message
+
+Test method providing the feedback message and starting with `test_`
 
       class Test01:
-        def test_b_is_not_True(self):
+        def test_b_is_not_true(self):
           assert b == True
+          # fails with message "b is not true"
+
         def test_a_is_not_one(self):
           assert a == 1
+          # fails with message "a is not one"