CODEWITHSUNDEEP
javaassertj
Antonio Dragos
Antonio Dragos

Reputation: 2803

test if a collection has exactly one element matching a predicate

With Assertj, I can use anyMatch to test if a collection has at least one element matching a predicate, e.g.

var list = List.of("abc", "xyz")
assertThat(list).anyMatch(element -> element.endsWith("xyz"));

But how do I test if a collection has exactly one element that matches a predicate?

Upvotes: 4

Views: 2163

Answers (1)

Ashley Frieze
Ashley Frieze

Reputation: 5443

How about using the filter? https://github.com/assertj/assertj-core/blob/9eceff23e5b019af3d09c3e9bbc58126d51c02b6/src/main/java/org/assertj/core/api/AbstractIterableAssert.java#L3283

var list = List.of("a", "b", "c!");

assertThat(list)
    .filteredOn(element -> element.endsWith("!"))
    .hasSize(1);

Upvotes: 10

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