Your problem is more related to your overall build. Gatling expects your simulation classes to be in src/test/scala
directory, but you can change its expectations. Just add the following setting into your build.sbt
:
scalaSource in Gatling := file("qa")
This will solve your problem in sbt
layer. You can prove it via running the `sbt ' in console and typing:
inspect gatling:scalaSource
or simply
galting:test
Another side of your problem is Intellij. I'm not sure if you have imported the whole project via Intellij sbt import or not. but I'm guessing that scala sbt plugin is not such a smart to recognize your specific changes to sources. You can
prove this by reimporting the whole project or just clicking refresh in your SBT tool window:

To open the tool window select View > Tool Windows > SBT from menu.
If it does not help (and I assume it won't) you can still add the qa
directory into test directories. Just select File > Project Structure from menu. Select Modules in the left pane. Select your project in middle pane. Select Sources tab, your directory and click Tests in the Mark as row. Commit your changes with OK button. See picture bellow:
Now your Intellij should compile your simulations.
Btw: files in project
directory are considered as separate module in IntelliJ, hence they compile. Same structure and point of view has also SBT, which considers
everything under this directory to be separate module. That explains why your files there compile.
Enjoy