feat(vitest): support vitest test runner

Add support for [vitest](vitest.dev) as a test runner using the `@stryker-mutator/vitest-runner` plugin.

This plugin currently supports minimal options:

```json
{
  "testRunner": "vitest",
  "vitest": { "configFile": "vitest.config.js" }
}
```

Limitations:

- The vitest runner only supports `"coverageAnalysis": "perTest"`.
- Some vitest options are always overridden by the plugin:
   - `threads: true`, `coverage: { enabled: false }`, `singleThread: true`

---------

Co-authored-by: Nico Jansen <jansennico@gmail.com>
Co-authored-by: danny12321 <dannyberkelaar@gmail.com>

e2e/package.json

@@ -44,6 +44,7 @@
     "ts-jest": "29.0.5",
     "ts-loader": "9.4.2",
     "ts-node": "10.9.1",
+    "vitest": "0.31.1",
     "typescript": "5.0.4",
     "webpack": "5.83.1",
     "webpack-cli": "5.1.1"
@@ -68,6 +69,7 @@
     "@stryker-mutator/cucumber-runner": "../packages/cucumber-runner",
     "@stryker-mutator/util": "../packages/util",
     "@stryker-mutator/tap-runner": "../packages/tap-runner",
-    "@stryker-mutator/typescript-checker": "../packages/typescript-checker"
+    "@stryker-mutator/typescript-checker": "../packages/typescript-checker",
+    "@stryker-mutator/vitest-runner": "../packages/vitest-runner"
   }
 }

e2e/test/mono-schema/test/invalid.json

@@ -14,5 +14,13 @@
     "features": [32],
     "tags": "tag",
     "profile": 42
+  },
+  "vitest": {
+    "options": {
+      "coverage": false
+    }
+  },
+  "tap": {
+    "specFiles": "{**/@(test|tests|__test__|__tests__)/**,**/*.@(test|tests|spec)}.@(cjs|mjs|js|jsx|ts|tsx)"
   }
 }

e2e/test/mono-schema/test/valid.json

@@ -28,5 +28,11 @@
     "features": ["my-feature.feature"],
     "profile": "stryker",
     "tags": ["@tag", "@tag2"]
+  },
+  "vitest": {
+    "configFile": "vitest.config.js"
+  },
+  "tap": {
+    "testFiles": "{**/@(test|tests|__test__|__tests__)/**,**/*.@(test|tests|spec)}.@(cjs|mjs|js|jsx|ts|tsx)"
   }
 }

e2e/test/mono-schema/verify/verify.js

@@ -95,6 +95,24 @@ describe('The Stryker meta schema', () => {
       },
       message: 'must be object',
     },
+    {
+      instancePath: '/tap',
+      keyword: 'additionalProperties',
+      message: 'must NOT have additional properties',
+      params: {
+        additionalProperty: 'specFiles',
+      },
+      schemaPath: '#/properties/tap/additionalProperties',
+    },
+    {
+      instancePath: '/vitest',
+      keyword: 'additionalProperties',
+      message: 'must NOT have additional properties',
+      params: {
+        additionalProperty: 'options',
+      },
+      schemaPath: '#/properties/vitest/additionalProperties',
+    },
   ].sort(orderByInstancePath);
 
   /**

e2e/test/vitest-noconfig/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "vitest-noconfig",
+  "version": "0.0.0",
+  "private": true,
+  "description": "A module to perform an integration test",
+  "main": "index.js",
+  "scripts": {
+    "pretest": "rimraf \"reports\"",
+    "test": "stryker run",
+    "posttest": "mocha --no-config --no-package --timeout 0 verify/verify.js",
+    "test:unit": "vitest run"
+  },
+  "author": "",
+  "license": "ISC"
+}

e2e/test/vitest-noconfig/src/add.ts

@@ -0,0 +1,3 @@
+export function add(num1: number, num2: number) {
+  return num1 + num2;
+}

e2e/test/vitest-noconfig/src/increment.ts

@@ -0,0 +1,6 @@
+
+export function increment(number: number) {
+  number++;
+  return number;
+}
+

e2e/test/vitest-noconfig/src/is-negative.ts

@@ -0,0 +1,7 @@
+export function isNegativeNumber(number: number) {
+  var isNegative = false;
+  if (number < 0) {
+    isNegative = true;
+  }
+  return isNegative;
+}

e2e/test/vitest-noconfig/src/negate.ts

@@ -0,0 +1,4 @@
+
+export function negate(number: number) {
+  return -number;
+}

e2e/test/vitest-noconfig/stryker.conf.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "../../node_modules/@stryker-mutator/core/schema/stryker-schema.json",
+  "testRunner": "vitest",
+  "concurrency": 1,
+  "coverageAnalysis": "perTest",
+  "reporters": ["json", "clear-text", "html", "event-recorder"],
+  "plugins": [
+    "@stryker-mutator/vitest-runner"
+  ]
+}

e2e/test/vitest-noconfig/tests/add.spec.ts

@@ -0,0 +1,9 @@
+import { add } from '../src/add';
+import { expect, test, describe } from 'vitest';
+
+describe('add', () => {
+  test('should be able to add two numbers', function () {
+    const actual = add(5, 2);
+    expect(actual).toBe(7);
+  });
+});

e2e/test/vitest-noconfig/tests/increment.spec.ts

@@ -0,0 +1,15 @@
+import { increment } from '../src/increment';
+import { expect, test, describe } from 'vitest';
+
+describe('increment', () => {
+
+  test('should be able to add one to a number', function () {
+    var number = 2;
+    var expected = 3;
+
+    var actual = increment(number);
+
+    expect(actual).toBe(expected);
+  });
+
+});

e2e/test/vitest-noconfig/tests/is-negative.spec.ts

@@ -0,0 +1,11 @@
+import { isNegativeNumber } from '../src/is-negative';
+import { expect, test, describe } from 'vitest';
+
+describe('math', () => {
+
+  test('should be able to recognize a negative number', function () {
+    const number = -2;
+    const result = isNegativeNumber(number);
+    expect(result).toBe(true);
+  });
+});

e2e/test/vitest-noconfig/tests/negate.spec.ts

@@ -0,0 +1,9 @@
+import { negate } from '../src/negate';
+import { expect, test, describe } from 'vitest';
+
+describe('negate', () => {
+  test('should be able negate a number', function () {
+    const actual = negate(2);
+    expect(actual).toBe(-2);
+  });
+});

e2e/test/vitest-noconfig/verify/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

e2e/test/vitest-noconfig/verify/verify.js

@@ -0,0 +1,7 @@
+import { expectMetricsJsonToMatchSnapshot } from '../../../helpers.js';
+
+describe('Verify stryker has ran correctly', () => {
+  it('should report correct score', async () => {
+    await expectMetricsJsonToMatchSnapshot();
+  });
+});

e2e/test/vitest-noconfig/verify/verify.js.snap

@@ -0,0 +1,22 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Verify stryker has ran correctly should report correct score 1`] = `
+Object {
+  "compileErrors": 0,
+  "ignored": 0,
+  "killed": 11,
+  "mutationScore": 78.57142857142857,
+  "mutationScoreBasedOnCoveredCode": 78.57142857142857,
+  "noCoverage": 0,
+  "pending": 0,
+  "runtimeErrors": 0,
+  "survived": 3,
+  "timeout": 0,
+  "totalCovered": 14,
+  "totalDetected": 11,
+  "totalInvalid": 0,
+  "totalMutants": 14,
+  "totalUndetected": 3,
+  "totalValid": 14,
+}
+`;