Test Gap
Test Gap Analysis reveals code changes that have not been tested on any of your (manual or automated) test stages. Such changes are 5x more likely to contain defects, which is why you should focus on them first.

Find more defects

Prevent inandvertently untested changes

Informed decisions
Tested changes
Less defects

Defects, Changes and Tests

Defects in new or changed code
It is no secret that new or changed code often causes defects. Therefore, you pay great attention to thoroughly testing new and changed functionality. Unfortunately, this is extremely hard to get right!
Test Gaps

In a study with Munich Re, we accompanied two releases of a business information system. In both releases over 50% of the changes were not tested. These Test Gaps slipped through their very structured, multi-stage testing process unnoticed. And they turned out to have a 5x higher defect probability!


Test Gap Analysis

Collect code changes

Teamscale’s Test Gap Analysis automatically collects all code changes from your version control system (e.g., Git or Subversion).

Record test coverage

Coverage profilers record which code is executed in your test environments and send the data to Teamscale for analysis.

This works for all types of tests, even manual ones, as well as for all common technologies, platforms and programming languages.

See untested changes

Teamscale's Test Gap Analysis combines the data on code changes and code executed in tests, to show you all untested changes in your code.

TGA Changes and Execution_square_2

Put it to Use

For individual features

As a tester, you may focus on the Test Gaps on the functionality you're currently testing. You see which code has changed in this context and what has not been tested. Consider putting “no Test Gaps” on your Definition of Done!

For the entire System

As a test manager, you may monitor Test Gaps throughout the code base, for any time frame (e.g. since the latest release), to steer testing resources based on risks. 

To grow your test suite

Test Gap Analysis shows you the gaps and who did the respective changes, to help you talk to the right people and come up with the right tests.

TGA System wide

Types of Tests

Automated and manual

Test Gap Analysis may consider both automated and manual tests. The coverage profiler in your test environment is independent of what or who drives the tests.

All test stages

Test Gap Analysis may consider tests on all test stages, from low-level unit tests in the CI to E2E acceptance test in a pre-live environment. All you need is a coverage profiler in the retrospective environment. 

All technologies

Test Gap Analysis is applicable to all technologies, platforms and programming languages, for which a coverage profiler exists - which is usually the case.

Test Aggregation_square

Experience Less Defects

Effectively reduce defects

Test Gap Analysis helps you effectively prevent defects from slipping into production.

Munich Re, for example, cut the number of production defects in half, thanks to Test Gap Analysis.

Reliably test all your changes

Test Gap Analysis helps you prevent that untested changes ever go into production without you knowing. It is a powerful tool, to replace your testers’ gut feeling by facts everyone shares.
Munich Re, for example, reduced the their Test Gap from more than 50% to below 10%, since they started using Test Gap Analysis.

Effectively steer your testing efforts

Test Gap Analysis enables you to make risk-based decisions on where to invest your precious testing resources. Identify high-stakes gaps and systematic leaks to do the best job you can.

Bugs with and without TGA_blue


Everything you need to know about Test Gap Analysis. Can’t find the answer you’re looking for? Please chat to our friendly team.

Where do most defects occur?

Most defects occur in new or changed code. Untested changes have a 5x times higher likelihood of still containing a defect.

Why do changes remain untested?

The reason usually is that information about changes is spread across different systems, teams and individuals. In the face of such incomplete information, no one holds the complete big picture.

What is code coverage?

We say some code (a method, function, line, branch, ...) is covered, when it is executed by a test. Note that this is different from feature coverage, which does not consider the actual code.

What is a coverage profiler?

A coverage profiler is a tool that attaches to your software system, to record which part of the code gets executed during runtime. There are quite different technical approaches to this, depending on the technology.

How to update Test Gap Analysis results?

Teamscale's Test Gap Analysis automatically updates whenever new changes are made or additional tests are run. You may concentrate on developing your product and use the Test Gaps to steer your testing efforts.

Does Test Gap Analysis ensure things work correctly?

No. Test Gap Analysis tells you where you missed things in your testing. Like with any testing, it cannot guarantee the absence of defects. Nor does it assess the quality of your tests. You still need good people doing a good job testing!

Should I close all Test Gaps?

No. Closing all Test Gaps should never be a goal in itself. Use the Test Gaps for informed decisions about whether you need additional tests and what for. And don't let "perfect" be the enemy of "good enough".

Experience Exchange

Would you like to exchange experiences on Test Gap Analysis?

Any complex analysis raises questions. Is it applicable to you at all? What experiences have other companies in your industry had with Test Gap Analysis? Are the technologies you use supported? To name just a few.

I have dealt with Test Gap Analysis for over 10 years. In research papers, speaking at industry conferences, talking to testers and test managers, and working with customers who have been using it for years.

I’m happy to chat with you about Test Gap Analysis!

Start using Test Gap Analysis

Don't miss your chance to deliver better software with Teamscale

Up to date

Latest writings

The latest news, events and insights from our team.

  • Events
  • Publications
  • Cases
  • Blog
Dr. Tobias Röhm • Dr. Sven Amann • Tobias Wiese • 2024
Dr. Elmar Jürgens • Jakob Rott • 2024
Fabian Streitel • Nadezhda Tonchev • 2024
Dr. Florian Deißenböck • Dr. Nils Göde • 2024
Mattis Kämmerer • Dr. Sven Amann • 2024
Dr. Elmar Jürgens • 2024
Trusted by the best teams