Add benchmarks for runtime with many files

benchmarks/runtime.bench.js

@@ -0,0 +1,104 @@
+'use strict';
+
+const { expect } = require('chai');
+const { Linter } = require('eslint');
+const times = require('ramda/src/times');
+const { runBenchmark, cpuSpeed } = require('./measure');
+const mochaPlugin = require('../');
+
+const recommendedRules = mochaPlugin.configs.recommended.rules;
+
+function lintManyFilesWithAllRecommendedRules({ numberOfFiles }) {
+    const linter = new Linter();
+
+    linter.defineRules(mochaPlugin.rules);
+
+    const config = {
+        rules: Object.fromEntries(Object.entries(recommendedRules).map(([ ruleName, ruleSettings ]) => {
+            const [ , ruleNameWithoutPrefix ] = ruleName.split('/');
+
+            return [ ruleNameWithoutPrefix, ruleSettings ];
+        })),
+        parserOptions: {
+            ecmaVersion: 2018
+        }
+    };
+
+    times((index) => {
+        const codeToLint = `
+            'use strict';
+            const assert = require('assert');
+            const sinon = require('sinon');
+            const sut = require('./sut');
+
+            describe('SUT ${index}', function () {
+                let fooStub;
+
+                before(() => {
+                    fooStub = sinon.stub(sut, 'foo');
+                });
+
+                after(() => {
+                    fooStub.restore();
+                });
+
+                beforeEach(function (done) {
+                    done();
+                });
+
+                afterEach(() => {
+                    fooStub.reset();
+                });
+
+                it('should work', async function () {
+                    const bar = {};
+
+                    await sut(bar);
+
+                    assert(fooStub.callCount === 42);
+                });
+
+                describe('nested suite', async () => {
+                    beforeEach(async function () {
+                        await sleep(200);
+                    });
+
+                    xit('doesn’t work yet', function () {
+                        sut();
+                    });
+                });
+
+                context('more context', function () {
+                    it.only('only here it works', () => {
+                        sut();
+                        assert(true);
+                    });
+                });
+            });
+        `;
+
+        linter.verify(codeToLint, config);
+    }, numberOfFiles);
+}
+
+describe('runtime', () => {
+    it('should not take longer as the defined budget to lint many files with the recommended config', () => {
+        const budget = 52000000 / cpuSpeed;
+
+        const { medianDuration } = runBenchmark(() => {
+            lintManyFilesWithAllRecommendedRules({ numberOfFiles: 350 });
+        }, 5);
+
+        expect(medianDuration).to.be.below(budget);
+    });
+
+    it('should not consume more memory as the defined budget to lint many files with the recommended config', () => {
+        const budget = 2400000;
+
+        const { medianMemory } = runBenchmark(() => {
+            lintManyFilesWithAllRecommendedRules({ numberOfFiles: 350 });
+        }, 5);
+
+        expect(medianMemory).to.be.below(budget);
+    });
+});