A Twitter friend recently asked me the following question:

I work in a Microsoft shop. We have 40 developers who use .NET (C#). We also have several manual testers and 5 automation engineers who developed our test automation solution in Python. However, our leadership wants to move everything completely to C#.

Would it be better to (a) train 40 .NET developers in Python to use the existing test solution or (b) train the testers in .NET and port the tests to C#?

This is a very tough question. It’s not as simple as asking for the best test automation language because there are people, positions, and solutions already in place. Honestly, I can’t give a conclusive answer without more context, but I can offer five points of advice.

What is the state of the Python test solution?

How big and how bad is the existing Python test automation solution? Rewriting tests that already work fine has low return-on-investment. However, rewriting tests that have problems like flakiness or false positives might be worthwhile. More tests means more time, too. Please read my article, Our Test Automation Has Problems. Should We Start Over?, to learn what problems would warrant a rewrite.

Why not have two test solutions?

If the existing Python tests are fine, then rewriting them is a huge opportunity cost. Instead of rewriting existing tests, developers and testers could spend their time writing only the new tests in a new C# solution. The Python solution would be “legacy” and would not have any new tests added to it. Old tests would disappear with deprecated features, too. Eventually, the C# tests would take over. The main drawback for this possibility is the continued maintenance of a Python stack.

Do the manual testers have any programming experience?

Many manual testers do not have strong programming skills. Some may not have any programming skills at all! They will have a big learning curve when training to do test automation. Python would be a much easier language for them to learn than C# because it is concise, readable, and friendly for beginners. Conversely, Python would be fairly easy for C# developers to learn as they go.

What advantages will conformity bring?

Retraining workers and rewriting code is no small task. From a business perspective, they are investment costs. There must be significant returns that outweigh the cost of the transition. Make sure those returns are known and real.

Will developers also automate tests?

Many teams choose to write their test automation code in the same language as the product code so that developers can more easily automate tests. However, in my experience, developers typically don’t write many tests, especially when others on the team are dedicated testers. Test automation is difficult and has unique challenges. Some developers have bad attitudes about testing, too. Changing the language probably won’t change the deeper issues.

Final Thoughts

The decision to choose between C# and Python for test automation is very personal for me. I faced this choice directly when I started working at PrecisionLender. Even though I deeply love Python, we chose to use C#. It was the right choice: we were a Microsoft shop with no test solution (yet) and no Python stack in place. My team and I have no regrets.

There is nothing with test automation that either language can’t do. Both are solid choices. The best choice for a team depends more upon the team’s situation than differences between these languages.