A Tour of C++ (2014)
Part 1: Getting started
Chapter 1: The basics of unit testing
Part 2: Core techniques
Chapter 3: Using stubs to break dependencies
Chapter 4: Interaction testing using mock objects
Chapter 5: Isolation (mocking) frameworks
Chapter 6: Digging deeper into isolation frameworks
Part 3: The test code
Chapter 7: Test hierarchies and organization
Chapter 8: The pillars of good unit tests
Part 4: Design and process
Chapter 9: Integrating unit testing into the organization
Chapter 10: Working with legacy code
Chapter 11: Design and testability
Appendix. Tools and frameworks