We can also simplify this using the Hamcrest matchers, to be:

```java
assertThat(similarity.similarity(v1, v1), closeTo(1, EPSILON));
```

You don't need to make this change - using `assertEquals` is fine - but if you feel like it, go ahead. I generally prefer the Hamcrest `assertThat` tests because I find them more readable, and you don't have to worry about getting the expected and actual values backwards.  You have the expected/actual values right in this file, so it's good :). But I often get them backwards when writing tests, and using `assertThat` gives me one less thing to worry about.