MUTT - Micro Unit Testing Tool (for browsers)

mutt.js

// MUTT - Micro Unit Testing Tool (for browsers)

let _testDepth = 0;

export function test(name, suite) {
  const title = `🐶 ${name}`;
  const ctx = {
    count: 0,
    failed: 0
  };

  _testDepth++;

  if (_testDepth > 1) console.group(title);
  else console.groupCollapsed(title);

  try {
    suite({
      equal(actual, expected, message) {
        assert(ctx, actual == expected, message);
      },
      notEqual(actual, expected, message) {
        assert(ctx, actual != expected, message);
      },
      fail(message) {
        assert(ctx, false, message);
      },
      ok(actual, message) {
        assert(ctx, actual, message);
      },
      notOk(actual, message) {
        assert(ctx, !actual, message);
      },
      is(actual, expected, message) {
        assert(ctx, actual === expected, message);
      },
      isNot(actual, expected, message) {
        assert(ctx, actual !== expected, message);
      },
      throws(block, message) {
        assertException(ctx, block, message, true);
      },
      doesNotThrow(block, message) {
        assertException(ctx, block, message, false);
      }
    });
  } catch (err) {
    console.error("Error running tests:", err);
  }

  if (ctx.count > 0) {
    if (ctx.failed === 0)
      console.log(`✅ ${ctx.count} of ${ctx.count} succeeded.`);
    else console.log(`💥 ${ctx.failed} of ${ctx.count} failed.`);
  }

  console.groupEnd(title);

  if (ctx.failed > 0) console.log(`🚨 ${name}: ${ctx.failed} Failure(s)`);

  _testDepth--;
}

function assertException(ctx, block, message, expectsThrow) {
  let threw = false;
  try {
    block();
  } catch (err) {
    threw = true;
  }
  assert(ctx, threw === expectsThrow, message);
}

function assert(ctx, assertion, message) {
  ctx.count++;
  console.assert(assertion, message);
  if (!assertion) ctx.failed++;
  else console.info(message);
}

export default test;

// Quick self-test
test("MUTT", (t) => {
  test("Setup", () => {
    const methods = Object.keys(t).sort().join(",");
    t.equal(
      methods,
      "doesNotThrow,equal,fail,is,isNot,notEqual,notOk,ok,throws",
      "Provides all assertion methods."
    );
  });

  test("Assertions", () => {
    t.ok(true, "ok(true)");
    t.notOk(false, "notOk(false)");
    t.equal(1, 1, "equal(1,1)");
    t.equal(1, "1", "equal(1,'1')");
    t.notEqual(1, 2, "notEqual(1,2)");
    t.is(1, 1, "is(1,1)");
    t.isNot(1, 2, "isNot(1,2)");
    t.isNot(1, "1", "isNot(1,'1')");
    t.doesNotThrow(() => {
      // Nothing to see here
    }, "doesNotThrow(() => {})");
    t.throws(() => {
      throw new Error("There was an error.");
    }, "throws(() => {})");
    // t.fail("Force a failure.");
  });
});