Tests

Tests are a way to ensure that your development environment is working as expected.

Running devenv test will build your environment and run the tests defined in enterTest.

If you have processes defined in your environment, they will be started and stopped for you.

Writing your first test

A simple test would look like:

{ pkgs, ... }: {
  packages = [ pkgs.ncdu ];

  enterTest = ''
    ncdu --version | grep "ncdu 2.2"
  '';
}

$ devenv test
✓ Building tests in 2.5s.
• Running tests ...
Setting up shell environment...
Running test...
ncdu 2.2
✓ Running tests in 4.7s.
✓ Tests passed. in 0.0s.

By default, the enterTest detects if .test.sh file exists and runs it.

Testing with processes

If you have processes defined in your environment, they will be started and stopped for you.

{ pkgs, ... }: {
  services.nginx = {
    enable = true;
    httpConfig = ''
      server {
        listen 8080;
        location / {
          return 200 "Hello, world!";
        }
      }
    '';
  };

  enterTest = ''
    wait_for_port 8080
    curl -s localhost:8080 | grep "Hello, world!"
  '';
}

$ devenv test
✓ Building tests in 2.5s.
✓ Building processes in 15.7s.
• Starting processes ...• PID is 113105
• See logs:  $ tail -f /run/user/1000/nix-shell.upTad4/.tmpv25BxA/processes.log
• Stop:      $ devenv processes stop
✓ Starting processes in 0.0s.
• Running tests ...
Setting up shell environment...
Running test...
ncdu 2.2
✓ Running tests in 4.7s.
• Stopping process with PID 113105
✓ Tests passed. in 0.0s.

Changing environment if testing

Added in 1.0.6

{ pkgs, lib, config, ... }: {
  processes = {
    backend.exec = "cargo watch";
  } // lib.optionalAttrs (!config.devenv.isTesting) {
    frontend.exec = "parcel serve";
  };
}

Provided functions for enterTest

wait_for_port <port> <timeout>: waits for a port to be open

If you’d like more functions to be added, take a look at NixOS tests and open an issue for what you need.