Starting a potential test runner that doesn't provide an opinionated assertion library.

testRunner.js

createRunner = () => {
  const beforeAlls = [];
  const afterAlls = [];
  const beforeEaches = [];
  const afterEaches = [];
  const tests = [];

  const test = (description, process) => {
    tests.push({
      description,
      process,
      hasPassed: false,
      hasExecuted: false,
    });
  };

  const beforeEach = (process) => {
    beforeEaches.push({process});
  };

  const afterEach = (process) => {
    afterEaches.push({process});
  };

  const beforeAll = (process) => {
    beforeAlls.push({process});
  };

  const afterAll = (process) => {
    afterAlls.push({process});
  };

  const executeProcess = async (process) => {
    const result = process();
    if (result instanceof Promise) {
      await result;
    }
  };

  const runTest = async (test) => {
    await Promise.all(beforeEaches.map(async (beforeEach) => {
      await executeProcess(beforeEach.process);
    }));
    try {
      await executeProcess(test.process);
      test.hasPassed = true;
    } catch (err) {
      test.hasPassed === false;
    }
    await Promise.all(afterEaches.map(async (afterEach) => {
      await executeProcess(afterEach.process);
    }));
  };

  const runTests = async () => {
    console.log('Starting tests');
    await Promise.all(beforeAlls.map(async (beforeAll) => {
      await executeProcess(beforeAll.process);
    }));
    await Promise.all(tests.map(async (test) => {
      await runTest(test);
      const status = test.hasPassed === true ? 'PASS' : 'FAIL';
      console.log(`${status} - ${test.description}`);
    }));
    await Promise.all(afterAlls.map(async (afterAll) => {
      await executeProcess(afterAll.process);
    }));
    const passedTests = tests.filter((test) => test.hasPassed);
    console.log('\n');
    console.log(`Passed ${passedTests.length}/${tests.length}`);
  };

  return { test, beforeAll, afterAll, beforeEach, afterEach, runTests };
};

runMyTests = () => {
  const runner = createRunner();
  runner.test('hello', () => { throw 'error'; });
  runner.runTests();
};