Asserting Strings with AssertJ

Table of Contents

介紹 matches 、 satisfies 驗證是否符合條件，類似的流暢或鍊式寫法，語法跟自然語言相近，對於編寫測試時力求容易閱讀及維護這之上提供了相當大的改進， Assert Strings in Java 本篇增加了範例，並透過單元測試來驗證產出結果。

檔案目錄

./
   +- src
       +- test
       |   +- org
       |       +- ruoxue
       |           +- spring_boot_168
       |               +- test
       |                   +- assertj
       |                       +- string
       |                           +- AssertingStringsTest.java

單元測試

Assertions Strings in Java 斷言字串的主要目的是取得字串以進行斷言。

matches

Assertions Strings in Java 驗證是否符合條件，若不成立，則會拋出 AssertionError 。

	@Test
	public void matches() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 12);

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 8);
	}

AssertJ 155
AssertJ

matchesWithDescription

Assertions Strings in Java 驗證是否符合條件，自訂描述訊息，若不成立，則會拋出 AssertionError 。

	@Test
	public void matchesWithDescription() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 12, "length");

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 8, "length");
	}

AssertJ 155
AssertJ

matchesThrowError

Assertions Strings in Java 驗證是否符合條件，自訂描述訊息，當不成立時，驗證拋出 AssertionError 。

	@Test
	public void matchesThrowError() {
		assertThatCode(() -> {
			String value = "AssertJ 155";
			System.out.println(value);
			assertThat(value).matches(s -> s.length() > 12, "length");
		}).isInstanceOf(AssertionError.class);

		assertThatCode(() -> {
			String value = "AssertJ";
			System.out.println(value);
			assertThat(value).matches(s -> s.length() > 8, "length");
		}).isInstanceOf(AssertionError.class);
	}

AssertJ 155
AssertJ

satisfies

Asserting Strings with Examples 驗證是否符合條件，若不成立，則會拋出 AssertionError 。

	@Test
	public void satisfies() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).satisfies(s -> {
			assertThat(s).isNotNull();
			assertThat(s).hasSize(11);
		});

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).satisfies(s -> {
			assertThat(s).isNotEmpty();
		}, s -> {
			assertThat(s).hasSize(7);
		});
	}

AssertJ 155
AssertJ

satisfiesAnyOf

Asserting Strings with Examples 驗證是否符合任一條件，若不成立，則會拋出 AssertionError 。

	@Test
	public void satisfiesAnyOf() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).satisfiesAnyOf(s -> {
			assertThat(s).isNotNull();
			assertThat(s).hasSize(11);
		});

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).satisfiesAnyOf(s -> {
			assertThat(s).isNotEmpty();
		}, s -> {
			assertThat(s).hasSize(99);
		});
	}

AssertJ 155
AssertJ

satisfiesThrowError

Asserting Strings with Examples 驗證是否符合條件，當不成立時，驗證拋出 AssertionError 。

	@Test
	public void satisfiesThrowError() {
		assertThatCode(() -> {
			String value = "AssertJ 155";
			System.out.println(value);
			assertThat(value).satisfies(s -> {
				assertThat(s).isNotNull();
				assertThat(s).hasSize(12);
			});
		}).isInstanceOf(AssertionError.class);

		assertThatCode(() -> {
			String value = "AssertJ";
			System.out.println(value);
			assertThat(value).satisfies(s -> {
				assertThat(s).isNotEmpty();
			}, s -> {
				assertThat(s).hasSize(8);
			});
		}).isInstanceOf(AssertionError.class);
	}

AssertJ 155
AssertJ

AssertingStringsTest.java

Asserting Strings with Examples 新增單元測試，驗證是否符合預期。

package org.ruoxue.spring_boot_168.test.assertj.string;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatCode;

import org.junit.jupiter.api.Test;

public class AssertingStringsTest {

	@Test
	public void matches() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 12);

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 8);
	}

	@Test
	public void matchesWithDescription() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 12, "length");

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).matches(s -> s.length() < 8, "length");
	}

	@Test
	public void matchesThrowError() {
		assertThatCode(() -> {
			String value = "AssertJ 155";
			System.out.println(value);
			assertThat(value).matches(s -> s.length() > 12, "length");
		}).isInstanceOf(AssertionError.class);

		assertThatCode(() -> {
			String value = "AssertJ";
			System.out.println(value);
			assertThat(value).matches(s -> s.length() > 8, "length");
		}).isInstanceOf(AssertionError.class);
	}

	@Test
	public void satisfies() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).satisfies(s -> {
			assertThat(s).isNotNull();
			assertThat(s).hasSize(11);
		});

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).satisfies(s -> {
			assertThat(s).isNotEmpty();
		}, s -> {
			assertThat(s).hasSize(7);
		});
	}

	@Test
	public void satisfiesAnyOf() {
		String value = "AssertJ 155";
		System.out.println(value);
		assertThat(value).satisfiesAnyOf(s -> {
			assertThat(s).isNotNull();
			assertThat(s).hasSize(11);
		});

		value = "AssertJ";
		System.out.println(value);
		assertThat(value).satisfiesAnyOf(s -> {
			assertThat(s).isNotEmpty();
		}, s -> {
			assertThat(s).hasSize(99);
		});
	}

	@Test
	public void satisfiesThrowError() {
		assertThatCode(() -> {
			String value = "AssertJ 155";
			System.out.println(value);
			assertThat(value).satisfies(s -> {
				assertThat(s).isNotNull();
				assertThat(s).hasSize(12);
			});
		}).isInstanceOf(AssertionError.class);

		assertThatCode(() -> {
			String value = "AssertJ";
			System.out.println(value);
			assertThat(value).satisfies(s -> {
				assertThat(s).isNotEmpty();
			}, s -> {
				assertThat(s).hasSize(8);
			});
		}).isInstanceOf(AssertionError.class);
	}
}

心得分享

Testing Java Strings with AssertJ 快速檢查物件是否滿足所有提供的斷言，搭配使用 Predicate 與 ThrowingConsumer 等接口，根據 lambda 表達式調用，驗證是否成立，若不成立，則會拋出 AssertionError， Asserting Strings with Examples 介紹 matches 、 satisfies 等方法，提供範例參考。