anti-patterns

Unit tests can leak mocks, setup and expectations if not isolated properly. Leaky data, passing from tests to tests can also hurt us.

Unless the test framework makes you use the same “test” prefix, don’t do it. It messes with separating and identifying unit tests.

Once people understand they actually need to write an assert, this unit tests anti-pattern appears almost immediately. Checking on null is a no-no.

Should we write tests for everything? Absolutely not. Tests that do not help us, cause us more pain while writing and maintaining them are waste. Here’s a common example I see all the time. We have code that translates data from one object or structure to another. Like this code that Read more…

Sometimes, tests imitate code, and not in a good way. Here’s our tested code: public String encode(String word) { String result = word + word.length(); return result; } And here’s our test: @Test public void howItsDone() { Encoder enc = new Encoder(); String input = “hello”; String result = enc.encode(input); Read more…

You’re testing the right thing, and the test passes, and everything is cool. Or is it? Check out this test: @Test public void encodeString_sizeAtEnd() { Encoder enc = new Encoder(); String result = enc.encode(“hello”); assertEquals(“hello5”, result); } This test looks ok. I bet that without looking at the implementation, you Read more…

Logic is everything that causes two or more possible paths. For example, if-else or switch-case. Logic is good for production code, but not unit tests.