Hamcrest 风格断言

– Start

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.*;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.junit.jupiter.api.Test;

//Hamcrest 风格断言，更贴近英语
class HamcrestAssertionTest {

	@Test
	void test() {
		String actual = "test";
		String expected = "test";
		String[] actualArray = new String[] {"a", "b"};
		List actualList = Arrays.asList(actualArray);
		Map actualMap = new HashMap<>();
		actualMap.put("name", "zhangsan");
		
		// assert Number
		assertThat(1.0, greaterThan(0.9));
		assertThat(1.0, greaterThanOrEqualTo(0.9));
		assertThat(1.0, lessThan(1.2));
		assertThat(1.0, lessThanOrEqualTo(1.2));
		assertThat(1.2, comparesEqualTo(1.2));
		assertThat(1.01, closeTo(1.0, 0.03));
		assertThat(Double.NaN, notANumber());
		
		// assert Text
		assertThat(actual, equalTo(expected));
		assertThat(actual, equalToIgnoringCase(expected));
		assertThat(actual, equalToCompressingWhiteSpace(expected));
		assertThat(actual, startsWith(expected));
		assertThat(actual, startsWithIgnoringCase(expected));
		assertThat(actual, endsWith(expected));
		assertThat(actual, endsWithIgnoringCase(expected));
		assertThat("", blankOrNullString());
		assertThat("", blankString());
		assertThat("", emptyOrNullString());
		assertThat("", emptyString());
		assertThat(actual, containsString("t"));
		assertThat(actual, containsStringIgnoringCase("t"));
		assertThat(actual, stringContainsInOrder("te"));
		assertThat(actual, both(containsString("t")).and(containsString("e")));
		assertThat(actual, either(containsString("t")).or(containsString("e")));
		assertThat("a", in(actualArray));
		assertThat("a", oneOf("a", "b"));
		assertThat(actual, hasLength(4));
		assertThat(actual, matchesPattern(".*"));
		assertThat(actual, matchesRegex(".*"));

		// assert Object
		assertThat(actual, equalToObject(expected));
		assertThat(actual, notNullValue());
		assertThat(null, nullValue());
		assertThat(actual, isA(String.class));
		assertThat(actual, instanceOf(String.class));
		assertThat(actual, any(String.class));
		assertThat(actual, sameInstance(expected));
		assertThat(actual, hasToString(expected));
		assertThat(actual, anything());
		assertThat(actual, is(anything())); // is 是语法糖，没有实际作用
		assertThat(actual, describedAs("actual is anything", anything()));
		
		// assert Map
		assertThat(actualMap, hasKey(equalTo("name")));
		assertThat(actualMap, hasValue(equalTo("zhangsan")));
		assertThat(actualMap, hasEntry(equalTo("name"), equalTo("zhangsan")));
		assertThat(actualMap, aMapWithSize(1));
		assertThat(new HashMap<>(), anEmptyMap());
		
		// assert Array and List
		assertThat(actualArray, array(equalTo("a"), equalTo("b")));
		assertThat(actualArray, arrayContaining(equalTo("a"), equalTo("b")));
		assertThat(actualArray, arrayContainingInAnyOrder(equalTo("a"), equalTo("b")));
		assertThat(actualArray, hasItemInArray(equalTo("a")));
		assertThat(actualArray, arrayWithSize(2));
		assertThat(new String[] {}, emptyArray());

		assertThat(actualList, hasItem(equalTo("a")));
		assertThat(actualList, hasItems(equalTo("a"), equalTo("b")));
		assertThat(actualList, contains(equalTo("a"), equalTo("b")));
		assertThat(actualList, containsInAnyOrder(equalTo("a"), equalTo("b")));
		assertThat(actualList, containsInRelativeOrder(equalTo("a"), equalTo("b")));
		assertThat(new ArrayList<>(), empty());
		assertThat(new ArrayList<>(), emptyIterable());
		assertThat(new ArrayList<>(), emptyCollectionOf(String.class));
		assertThat(actualList, everyItem(hasLength(1)));
		assertThat(actualList, hasSize(2));
		assertThat(actualList, iterableWithSize(2));

		// assert Beans
//		assertThat(actual, hasProperty("value"));
		
		// allOf, like Java &&
		// anyOf, like Java ||
		// not,   like Java !
		assertThat(actual, allOf(is("test"), is(not(("")))));
		assertThat(actual, anyOf(is(""), is(not(("")))));
		assertThat(actual, is(not("")));
	}

}

– 更多参见：Hamcrest 精萃
– 声 明：转载请注明出处
– Last Updated on 2019-08-13
– Written by ShangBo on 2019-08-13
– End