How Unit Tests Prove Correctness ........................................................................................................ 27
Prove Contract is Implemented ........................................................................................................ 27
Prove Computational Results ........................................................................................................... 28
Prove a Method Correctly Handles an External Exception .............................................................. 32
Prove a Bug is Re-creatable ............................................................................................................. 34
Prove a Bug is Fixed ......................................................................................................................... 35
Prove Nothing Broke When Changing Code .................................................................................... 35
Prove Requirements Are Met ........................................................................................................... 35
Chapter 4 Strategies for Implementing Unit Tests .............................................................................. 37
Starting From Requirements .................................................................................................................. 37
Prioritizing Computational Requirements ......................................................................................... 37
Select an Architecture ....................................................................................................................... 38
Maintenance Phase .......................................................................................................................... 38
Determine Your Process ........................................................................................................................ 39
Test-Driven Development ................................................................................................................. 39
Code First, Test Second ................................................................................................................... 41
No Unit Tests .................................................................................................................................... 41
Balancing Testing Strategies ............................................................................................................ 42
Chapter 5 Look before You Leap: The Cost of Unit Testing ............................................................... 43
Unit Test Code vs. Code Being Tested ................................................................................................. 43
Unit Test Code Base May Be Larger Than Production Code........................................................... 43
Maintaining Unit Tests ........................................................................................................................... 44
Does Unit Testing Enforce an Architecture Paradigm? ......................................................................... 44
Unit Test Performance ........................................................................................................................... 45
Mitigating Costs ..................................................................................................................................... 45
Correct Inputs ................................................................................................................................... 45
Avoiding Third-party Exceptions ....................................................................................................... 46
