Over the years I've seen, heard, and been in many conversations about the tools testers must learn. So many specific tools mentioned in that time, but I prefer an answer like this:
Learn the tools that are important for your context.
Perhaps that sounds like a cop-out, because it means testers will have to think about what they're doing, why they're doing it, the results they want to get from it, ways that they might get those results, the relative trade-offs of alternative approaches, how deep to go, the amount of time it's worth investing, when to invest it, and so on.
Tough.
There are easier alternatives. For example, just learn whatever tools someone on LinkedIn said that someone else on Linked said that someone else on LinkedIn said that someone else on LinkedIn said that ...
But that's a merry-go-round anyone would soon want to get off.
If you were asking the question and urged me to be specific I'd point you to My Favourite Tool.
If you read it and then continued nagging me for something very specific I might say to learn just enough of the key tooling that other people on your team use: IDEs, source control, visualisation, monitoring, etc. Those things are all gateways to information below the surface of your application and give you interactional expertise, which in turn greases the wheels of respect and collaboration.
I could ask you to think about the information you'd like to be able to have to do your job better but currently don't have and to research tools that could get it. You could consider using a tool that can help you to build the tool you need, or team up with someone who already knows that kind of tooling.
Maybe I'd also suggest that you keep an eye on what's happening elsewhere in your company, the industry, and the world. You might be looking for a job at some point: what do you think you would need to be able to say or demonstrate to make yourself marketable? What role do tools play in that, and to what extent?
Finally I'm pretty sure I'd ask what you'd like to learn about, just for yourself, for your own interest and satisfaction. And I'd suggest you try to find a way to do that in your work, where it's justifiable enough for some task.
By this point, though, I'd hope you'd see that in these answers I'm merely helping you to do what I suggested at the start: look at your context(s) and find the important tools.
Image: Emine Karakurt on Unsplash
