How to run rails tests in Visual Studio Code

Visual Studio is great. It's very slim and quite fast, at least when updated to the M1 version.
The testing support for rails seems to be quite outdated. There is a plugin Ruby Test Explorer but it looks like it needs updating for using the new rails test runner rails test. In the end, it's quite simple to actually run tests on your own and have 100% control over it. This will also allow you to rerun the last test, which is a critical productivity feature.

What you will get

With the method I show here, you can customise your test running as you wish. In the end, you will have the following shortcuts:

run all tests: ctrl+t ctrl+a (bin/rails test)
run all tests in current file: ctrl+t ctrl+f (bin/rails test {file})
run test under cursor: ctrl+t ctrl+l (bin/rails test {file:line})
rerun last test: ctrl+t ctrl+t

The method

Create a custom script

To gain the ability to rerun tests, we have to somehow store what we already ran. I am sure, there is an easier way within VSCode, but this method works for sure:

• Create a file bin/editor-test
• touch bin/editor-test && chmod +x bin/editor-test

Add the following script:

#!/usr/bin/env bash

# used to run tests with editor and saving the last run so we can repeat.
# for each test run it will save the last args in "tmp/editor-test-last-args".
# usage
# run file:
#   bin/editor-test some_file.rb:12
# run all:
#   bin/editor-test
# run last:
#   bin/editor-test run-last

set -e

if [ "$1" = "run-last" ]; then
  if [[ -f "tmp/editor-test-last-args" ]]; then
    bin/rails test "$(<tmp/editor-test-last-args)"
  else
    echo "No last test saved (file tmp/editor-test-last-args does not exist)"
  fi
else
  echo $@ > tmp/editor-test-last-args
  bin/rails test $@
fi

This provides you will the possibility to rerun tests from the console by storing the last test args in tmp/editor-test-last-args. Now, lets hook up vscode.

Setup custom VSCode Tasks

This is a per-project task file, so you could customize this per project.

Run the vscode command (cmd+shift p) "Tasks: Configure Task" and configure the following tasks:

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "repeat last test",
            "type": "shell",
            "command": "bin/editor-test run-last",
            "problemMatcher": [],
            "presentation": {
                "clear": true
            },
        },
        {
            "label": "launch tests for project",
            "type": "shell",
            "command": "bin/editor-test",
            "problemMatcher": [],
            "presentation": {
                "clear": true
            },
        },
        {
            "label": "launch tests for current file",
            "type": "shell",
            "command": "bin/editor-test ${file}",
            "problemMatcher": [],
            "presentation": {
                "clear": true
            },
        },
        {
            "label": "launch test for current line",
            "type": "shell",
            "command": "bin/editor-test ${file}:${lineNumber}",
            "problemMatcher": [],
            "presentation": {
                "clear": true
            },
        }
    ]
}

Setup keybindings

To have perfect productivity, lets create some keybindings:

{
    "key": "ctrl+t ctrl+a",
    "command": "workbench.action.tasks.runTask",
    "args": "launch tests for project"
},
{
    "key": "ctrl+t ctrl+f",
    "command": "workbench.action.tasks.runTask",
    "args": "launch tests for current file"
},
{
    "key": "ctrl+t ctrl+l",
    "command": "workbench.action.tasks.runTask",
    "args": "launch test for current line"
},
{
    "key": "ctrl+t ctrl+t",
    "command": "workbench.action.tasks.runTask",
    "args": "repeat last test"
},

Conclusion

There you have it. Super simple, easy to customise test running. This approach will work with every technology, not only rails and no need for plugins.