View Source VS Code Setup

If you are using Visual Studio Code, there are a couple of things that you can do to smooth out the workflow of running and updating your tests.

Custom tasks for testing

VS Code supports custom tasks, which allow you to, among other things, run command-line tools using editor-contextual information like the project you're working on, the file you're in, or the line you're on. Custom tasks are accessible by running the command Tasks: Run Task, but can also be bound to keyboard shortcuts (see below).

I personally use three custom tasks for testing:

• Run tests
• Run tests in current file
• Run test at cursor

To set these up:

1. Run the command Tasks: Open User Tasks. This will open your global tasks.json that will apply to all projects. (You can optionally use a local .vscode/tasks.json file per-project.)
2. Add the three tasks below and save the file.

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Run tests",
      "type": "shell",
      "command": "mix",
      "args": ["test"],
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "presentation": {
        "focus": true
      },
      "group": "test"
    },
    {
      "label": "Run tests in current file",
      "type": "shell",
      "command": "mix",
      "args": ["test", "${relativeFile}"],
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "presentation": {
        "focus": true
      },
      "runOptions": {
        "reevaluateOnRerun": false
      },
      "group": "test"
    },
    {
      "label": "Run test at cursor",
      "type": "shell",
      "command": "mix",
      "args": ["test", "${relativeFile}:${lineNumber}"],
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "presentation": {
        "focus": true
      },
      "runOptions": {
        "reevaluateOnRerun": false
      },
      "group": "test"
    }
  ]
}

Once saved, these tasks should immediately be available through Tasks: Run Task or Tasks: Run Test Task.

Keyboard shortcuts

To assign keyboard shortcuts to the three tasks created above:

1. Run Preferences: Open Keyboard Shortcuts (JSON).
2. Add the shortcuts below and save the file.

{
  "key": "ctrl+space a",
  "command": "workbench.action.tasks.runTask",
  "args": "Run tests"
},
{
  "key": "ctrl+space f",
  "command": "workbench.action.tasks.runTask",
  "args": "Run tests in current file"
},
{
  "key": "ctrl+space c",
  "command": "workbench.action.tasks.runTask",
  "args": "Run test at cursor"
},

The shortcuts above represent my own personal preferences and can be replaced with whatever you'd prefer.