add a summary at the end

12-unit-test-eg.org

@@ -185,3 +185,21 @@ struct decimal *convert_temperature(struct decimal *dp, uint16_t v)
   return dp;
 }
 #+END_SRC
+** Think about the maths
+Perhaps it would have been better to understand the maths involved before trying to write the code.
+
+That is, we wish to find the integer solutions $a$, $b$ to:
+\[ a + b/100 = x / 100 - 39.6 \]
+for integer values of $x$ in the range $[0, 65536)$.
+
+I leave it to the reader to try and find the full solution. Possibly this solution will be neater than our final version above!
+* Summary
+Although it can be daunting to set up your first test case, once you have done it, additional test cases are much easier.
+
+The advantage of working this way is that it /becomes/ much faster to develop correct code even though it may be slightly slower to begin with.
+I encourage you to stick with it!
+
+* Further exercises
+As a further exercise, you might like to test out the next function that we need to write, which is to print out the integer and fractional part on the screen using =printf=.
+As a first go, you may find it easier just to manually check that it prints the right output.
+It is possible to automatically check the output but this requires you to "mock" =printf=.