>Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style
I'm not advocating for TDD (the programmer methodology in the IDE) but the author's explanation about "test code" isn't correct. Code written for explicit purposes of a test to exercise other code has been shown to increase correctness. E.g. SQLite database has 711x more test code than the core engine code.[1] (I made a previous comment why this is possible: https://news.ycombinator.com/item?id=15593121)
Low-level infrastructure code like database engines, string manipulation libraries, crypto libraries, math libraries, network protocol routines, etc can benefit from a suite of regression tests.
It's the high-level stuff like GUIs in webpages being tested with Selenium or LoadRunner that has conflicting business value because altering one pixel can have a cascading effect of breaking a bunch of fragile UI test scripts.
I'm not advocating for TDD (the programmer methodology in the IDE) but the author's explanation about "test code" isn't correct. Code written for explicit purposes of a test to exercise other code has been shown to increase correctness. E.g. SQLite database has 711x more test code than the core engine code.[1] (I made a previous comment why this is possible: https://news.ycombinator.com/item?id=15593121)
Low-level infrastructure code like database engines, string manipulation libraries, crypto libraries, math libraries, network protocol routines, etc can benefit from a suite of regression tests.
It's the high-level stuff like GUIs in webpages being tested with Selenium or LoadRunner that has conflicting business value because altering one pixel can have a cascading effect of breaking a bunch of fragile UI test scripts.
[1] https://www.sqlite.org/testing.html