Comment by Arainach

When issues happen, it is almost never just one person's fault.

Just trace the Whys:

1) Why did the bug happen? These lines of code 2) Why wasn't that caught by tests? The test was broken / didn't exist 3) How was the code submitted without a test? The reviewer didn't call it out.

Arguing about percentages doesn't matter. What matters is fixing the team process so this doesn't happen again. This means formally documented standards for test coverage and education and building team culture so people understand why it's important.

It's not "just the author's fault". That kind of blame game is toxic to teams.