I've been involved with many projects in several companies because I've been a developer for a long time and I'm a contractor.
I estimate that less than 20% of projects are methodically tested. With methodically tested I mean any testing beyond ad-hoc no plan testing.
I also estimate that less than 10% of projects are thoroughly methodically tested where they have dedicated testers as part of the team, test plan document, where developers write automated tests and then they also track test coverage and measure results.
- What are your percentage estimates about this issue?
- What's your professional experience regarding software testing?
Since methodical testing question may get quite biased answers (people like to brag about being superior to others) I encourage other developers (those that're not exposed to methodical testing) to provide their answer as well, because otherwise it will look like testing is being done everywhere... except at your company.