A learning Example meant to teach a friend of mine about unit testing.
recommended way to run the test in the source dir:
php -S localhost:8000 -t ./and then opening browser at the url http://localhost:8000/run-test.php
A minimal profiler (that requires changes to the code) was added to demonstrate why the optimized version is faster
just compare the results of http://localhost:8000/profile-the-optimized-version.php
and http://localhost:8000/profile-the-slow-version.php
Total operation time is calculated c * n where c is the time taken per operation and n is the number of
operation. Many people would start reducing the c, but that would not be event visible for algorithms of high
complexities.
As in this example the complexity of the slow fibonacci is around (2^(n * 0.6)) in other words o(2^(n/2)) - O(2^n) and the optimized version complexity is around 2n, in other words O(n).