Confused regarding .dir-locals.el and projectile

Question

I have a python project, it has tests and I can execute them from the command line. I just read about .dir-locals.el in the projectile documentation and I want to execute tests from inside emacs using projectile.

So I create a .dir-locals.el file like:

((nil .
      (
       (projectile-project-test-cmd . "pytest --color=no")
       )))

The variable is set, but when do C-c p P (or M-x projectile-test-project) It asks for the command with Test command: (If I type there pytest --color=no, it will execute perfectly)

The documentation says that it is possible to avoid the question setting the variable compilation-read-command to no nil.

((nil .
      ((compilation-read-command . nil)
       (projectile-project-test-cmd . "pytest --color=no")
       )))

But if I do that, C-c p P stops asking, but it doesn't execute the tests, it executes a Compilation (!)

This is the result:

-*- mode: compilation; default-directory: "~/tmp/tsp/" -*-
Compilation started at Sat Oct 31 02:05:42



Compilation finished at Sat Oct 31 02:05:42

Would you mind to point me what I am doing wrong?

Answer 1

According to the docstring of projectile-test-command, this function first check projectile-test-cmd-map for the last command. It is likely you inadvertently invoked an empty "" command in that emacs session, and that empty command was stored inside the hash-table. The problem will probably disappear when you restart emacs or invoke (clrhash projectile-test-cmd-map) to clear the hash-table.

It's worth mentioning though, according to the doc, compilation-read-command maybe risky if used as a file-local variable. So I'm not sure if it's a good idea to put this in your .dir-locals.el. Perhaps it's better to set it globally (or set inside emacs customization interface).