How (Not) to Measure Quality

@MichaKutz

@mkutz@mstdn.social

Change Fail Rate

 08:07:23 Deploy basket-service ✓
09:06:11 Migrate checkout-service DB ✓
09:56:54 Deploy checkout-service ✓

 08:07:23 Deploy basket-service ✓
09:06:11 Migrate checkout-service DB ✓
09:56:54 Deploy checkout-service ✓
10:19:44 Deploy order-managment-service ✗
10:39:27 Rollback order-managemet-service ✓

 08:07:23 Deploy basket-service ✓
09:06:11 Migrate checkout-service DB ✓
09:56:54 Deploy checkout-service ✓
10:19:44 Deploy order-managment-service ✗
10:39:27 Rollback order-managemet-service ✓
11:09:59 Update database cluster ✓
12:27:32 Migrate order-managemet-service DB ✓
13:19:22 Deploy order-managemet-service ✓

 08:07:23 Deploy basket-service ✓
09:06:11 Migrate checkout-service DB ✓
09:56:54 Deploy checkout-service ✓
10:19:44 Deploy order-managment-service ✗
10:39:27 Rollback order-managemet-service ✓
11:09:59 Update database cluster ✓
12:27:32 Migrate order-managemet-service DB ✓
13:19:22 Deploy order-managemet-service ✓
14:45:55 Update database-cluster ✗
15:50:49 Update database-cluster ✓

 08:07:23 Deploy basket-service ✓
09:06:11 Migrate checkout-service DB ✓
09:56:54 Deploy checkout-service ✓
10:19:44 Deploy order-managment-service ✗
10:39:27 Rollback order-managemet-service ✓
11:09:59 Update database cluster ✓
12:27:32 Migrate order-managemet-service DB ✓
13:19:22 Deploy order-managemet-service ✓
14:45:55 Update database-cluster ✗
15:50:49 Update database-cluster ✓
16:39:11 Deploy product-service ✓
17:44:56 Deploy customer-data-service ✓ 08:07:23 Deploy basket-service ✓
09:06:11 Migrate checkout-service DB ✓
09:56:54 Deploy checkout-service ✓
10:19:44 Deploy order-managment-service ✗
10:39:27 Rollback order-managemet-service ✓
11:09:59 Update database cluster ✓
12:27:32 Migrate order-managemet-service DB ✓
13:19:22 Deploy order-managemet-service ✓
14:45:55 Update database-cluster ✗
15:50:49 Update database-cluster ✓
16:39:11 Deploy product-service ✓
17:44:56 Deploy customer-data-service ✓

How safe?

Hi, I'm Michael Kutz. I'm a developer… who prefers to continuously produce working software over bug fixing phases. Hence, I'm also a tester and test automation expert. I also enjoy working in an organization where decisions are made by those who can own them. Hence, I like working closely with management. In each of my jobs so far, at some point, somebody tried to measure the quality of the software we were producing… the result of their efforts was always less than satisfying. The latest attempt led me to finally sit down think why that is. This talk is the result of that thinking…

@MichaKutz @mkutz@mstdn.social

	@Test
	void strike() {
	var game = new Game();
	var firstRollPins = 10;
	var secondRollPins = 5;
	var thirdRollPins = 3;
	game.roll(firstRollPins);
	game.roll(secondRollPins);
	game.roll(thirdRollPins);

	var score = game.score();

	assertThat(score)
	.isEqualTo(
	firstRollPins +
	(secondRollPins + thirdRollPins) * 2);
	}

	@Test
	void strike() {
	var game = new Game();
	var firstRollPins = 10;
	var secondRollPins = 5;
	var thirdRollPins = 3;
	game.roll(firstRollPins);
	game.roll(secondRollPins);
	game.roll(thirdRollPins);

	var score = game.score();

	assertThat(score)
	.isEqualTo(
	firstRollPins +
	(secondRollPins + thirdRollPins) * 2);
	}

	@Test
	void strike() {
	var game = new Game();
	var firstRollPins = 10;
	var secondRollPins = 5;
	var thirdRollPins = 3;
	game.roll(firstRollPins);
	game.roll(secondRollPins);
	game.roll(thirdRollPins);

	var score = game.score();

	assertThat(score)
	.isEqualTo(
	firstRollPins +
	(secondRollPins + thirdRollPins) * 2);
	}

	public int score() {
	int score = firstRoll + secondRoll;
	if (previous != null) {
	if (previous.strike) {
	score *= 2;
	} else if (previous.spare) {
	score += firstRoll;
	}
	}
	return score;
	}

	@Test
	void strike() {
	var game = new Game();
	var firstRollPins = 10;
	var secondRollPins = 5;
	var thirdRollPins = 3;
	game.roll(firstRollPins);
	game.roll(secondRollPins);
	game.roll(thirdRollPins);

	var score = game.score();

	// assertThat(score)
	// .isEqualTo(
	// firstRollPins +
	// (secondRollPins + thirdRollPins) * 2);
	}

	08:07:23 Deploy basket-service ✓
	09:06:11 Migrate checkout-service DB ✓
	09:56:54 Deploy checkout-service ✓