If you are using TDD, as you should be 🤨, you have been a victim of at least one of those anti-patterns.
We will discuss 5 🖐 of them, looking at their Causes, Problems and how to avoid them.
1️⃣ The Liar 🤥
Passes all tests with no useful assertions
-
Causes
- Chasing test coverage
-
Problem
- Illusiuon of coverage
- Waste of time and money
-
Correction
- Delete the tests
@Test
public void liarTest(){
ShipmentService shipmentService = new ShipmentService();
shipmentService.doStuff();
assertTrue(true);
}
2️⃣ Excessive Setup 🧰
Requires a lot of work to prepare the test
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Causes
- Poor modularity and poor separation of concerns in the design
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Problem
- Tests and code are highly coupled
- Hard to maintain
- This will slow down the development to a halt
-
Correction
- Improve abstraction and separation of concerns in the code
- Write pure functions
@Test
public void excessiveSetup (){
// set up beginning
VerificationService verificationService = new VerificationService();
ShipmentRepository shipmentRepository = new ShipmentRepository();
ShipmentService shipmentService = new ShipmentService(verificationService, shipmentRepository);
Product product = new Product("Product");
Owner owner = new Owner("owner");
Count count = new Count(100);
Shipment shipment = new Shipment(product, owner, count);
ShipmentDetail shipmentDetail = new ShipmentDetail(shipment);
// set up ending
// rest of test
}
3️⃣ The Giant 💥
Has multiple assertions in a single test
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Causes
- Testing too much things at the same time
-
Problem
- Hard to understand
- Test and code are highly coupled
- Hard to maintain
-
Correction
- Decompse the test into multiple tests
@Test
public void theGiant (){
ShipmentService shipmentService = new ShipmentService();
Shipment shipment = new Shipment("product", "owner", 2);
shipmentService.processShipment_Free(shipment);
assertEquals("productUpdated", shipment.getProduct());
assertEquals("ownerUpdated", shipment.getOwner());
assertEquals(5, shipment.getCount());
Shipment shipment2 = new Shipment("product2", "owner2", 9);
shipmentService.processShipment_Premium(shipment);
ssertEquals("productPremium", shipment2.getProduct());
assertEquals("ownerPremium", shipment2.getOwner());
assertEquals(41, shipment2.getCount());
// could go on even further
//....
}
4️⃣ The Mockery 🤡
Uses so many mocks that the real code isn't tested
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Causes
- Excessive setup
-
Problems
- Doesn't test anything
-
Correction
- Review code design
- Improve abstraction and seperation of concerns
@Test
public void theMockery (){
doReturn("test").when(serviceMock).getValue();
doReturn(true).when(serviceMock).isValid();
assertEquals("test", serviceMock.getValue());
assertTrue(serviceMock.isValid());
}
5️⃣ The inspector 🧐
Adding functions that are only used in the tests
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Causes
- Chasing test coverage
-
Problems
- Waste of time and money since it doesn't test production code
-
Corrections
- Delete those functions.
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