Hamcrest Test Framework

 Hamcrest란?

test framework을 이용하여 단위 테스트 진행 시 assert를 유연하게 하기 위해 matcher를 이용하여 좀 더 쉽고 확장성 있는 assert를 하기 위해 만들어진 framework이다. 

Hamcrest는 처음부터 test framework과 통합되도록 설계되어 JUnit, TestNG와 함께 사용할 수 있다.

maven dependency

<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-library</artifactId>
    <version>2.2</version>
    <scope>test</scope>
</dependency>

Hamcrest code

assertThat(actual, is(equalTo(expedted);
assertThat(result, instanceof String);
assertThat(result, is(hasItem(anyOf(equalTo("x", equalTo("y"), equalTo("z"))))));

Hamcrest Matcher 

allOf - matches if all matchers match (short circuits)

anyOf - matches if any matchers match (short circuits)

not - matches if the wrapped matcher doesn’t match and vice

equalTo - test object equality using the equals method

is - decorator for equalTo to improve readability

hasToString - test Object.toString

instanceOf, isCompatibleType - test type

notNullValue, nullValue - test for null

sameInstance - test object identity

hasEntry, hasKey, hasValue - test a map contains an entry, key or value

hasItem, hasItems - test a collection contains elements

hasItemInArray - test an array contains an element

closeTo - test floating point values are close to a given value

greaterThan, greaterThanOrEqualTo, lessThan, lessThanOrEqualTo

equalToIgnoringCase - test string equality ignoring case

equalToIgnoringWhiteSpace - test string equality ignoring differences in runs of whitespace

containsString, endsWith, startsWith - test string matching