Are there any JUnit tests in SWT (or Platform?) that spawn a child process?

[jonahgraham]

I'm working on improving the clipboard for GTK4 in #2126

The Gdk clipboard behaves differently if you are copy-pasting between processes vs within the same process (is local). So to test the code thoroughly I need to copy-paste between processes.

Are there existing examples of this in the SWT (or wider Platform) testsuite?

On Linux there are some command line programs that can do it. Perhaps I can launch those iff on Linux. Alternatively a cross-platform option of launching another SWT program from within a test (e.g. add a main method to current class).

Any other thoughts?

[laeubi]

Alternatively a cross-platform option of launching another SWT program from within a test (e.g. add a main method to current class).

There is org.eclipse.swt.program.Program and if you call Program.findProgram("txt") you hopefully will get something that is a text editor but the control over the program is quite limited.

Java has the ToolProvider where you maybe can get something more or less platform independent as well.

One could also think about spawning another java process that starts a Single-File Source-Code Program, this can then e.g. open a Swing UI quite easily and you can ask it to copy/past using Stdin/out commands... that would be most flexible I think.

[jonahgraham]

open a Swing UI quite easily and you can ask it to copy/past using Stdin/out commands... that would be most flexible I think.

I like this idea. It also benefits from not using SWT at both ends of the copy-paste, leading it to be more likely that we detect bugs in our implementation, and should be cross-platform too.

[jonahgraham]

In the end I did it by letting JDT compile my independent code as part of the project and then extracting the needed class files* and running System.getProperty("java.home") + "/bin/java" **.

I used RMI for communication as it meant I didn't have to write any new serializing/deserializing code.

You can see that in action here: #2541

* Open question in the PR is if I can run the jar file directly (for cases when testing from a bundled jar).

** Not yet tested on non Linux or in Maven or in aggregator build. My focus has been running it in Eclipse IDE so far with JDT but the other combinations will come now that I created the PR

[laeubi]

@jonahgraham you can build additional jars during compilation if you look how we produce them for the ant runs you will find some examples, but of course it will work this way as well.