Introduction to AssertJ - AssertJ 155

Introduction to AssertJ – AssertJ 155

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  • Post last modified:2023-09-18

Introduction to AssertJ - AssertJ 155

介紹 AssertJ 一個開源的程式庫,用於在 Java 測試中編寫流暢且豐富的斷言,透過 AssertJ Introduction 流式斷言,可以大幅提升斷言效率,讓開發者體驗更流暢的驗證斷言,本篇增加了範例,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
       |                       +- IntroductionAssertJTest.java   

Dependencies

提供了一系列類別和實用方法,支援如下:

Standard Java
Java 8
Guava
Joda Time
Neo4J and
Swing components

介紹使用基本模組 AssertJ-core ,從 AssertJ 3.5.1 版本開始,就已經支援 Java 8 ,因此須將引用其程式庫,若使用 Java 7 或是更早之前的版本,則須引用 AssertJ 2.x.x。

Maven

pom.xml

<dependency>
    <groupId>org.assertj</groupId>
    <artifactId>assertj-core</artifactId>
    <version>3.23.1</version>
    <scope>test</scope>
</dependency>

Gradle

build.gradle

dependencies {
	testImplementation "org.assertj:assertj-core:3.23.1"
}

單元測試

Fluent Assertions Java Library 斷言物件的主要目的是取得物件以進行斷言。

Fruit

建立 Fruit 類別,覆寫 toString ,定義屬性和方法,用來建立一個物件。

	@NoArgsConstructor
	@Getter
	@Setter
	public static class Fruit {
		private String name;
		private double quantity;
		private int type;
		private List<String> origins = new ArrayList<>();

		public Fruit(String name, double quantity, int type) {
			this.name = name;
			this.quantity = quantity;
			this.type = type;
		}

		public String toString() {
			ToStringBuilder builder = new ToStringBuilder(this, ToStringStyle.JSON_STYLE);
			builder.appendSuper(super.toString());
			builder.append("name", name);
			builder.append("quantity", quantity);
			builder.append("type", type);
			builder.append("origins", origins);
			return builder.toString();
		}
	}

Boolean Assertions

驗證是否真假,若不成立,則會拋出 AssertionError 。

	@Test
	public void booleanAssertions() {
		String value = "AssertJ";
		System.out.println(value);
		assertThat(value.startsWith("A")).isTrue();

		String value2 = "";
		System.out.println(value2);
		assertThat(value2.isEmpty()).isTrue();
	}
AssertJ

Character Assertions

Fluent Assertions Java Library 驗證字元是否符合條件,若不成立,則會拋出 AssertionError 。

	@Test
	public void characterAssertions() {
		char value = 'A';
		System.out.println(value);
		assertThat(value).isNotEqualTo('a').inUnicode().isLessThanOrEqualTo('b').isUpperCase();

		char value2 = '1';
		System.out.println(value2);
		assertThat(value2).isEqualTo('1').isIn('1', '5').isGreaterThan('/');
	}
A
1

String Assertions

Fluent Assertions Java Library 驗證字串是否符合條件,若不成立,則會拋出 AssertionError 。

	@Test
	public void stringAssertions() {
		String value = "AssertJ 155";
		System.out.println(value);
		Condition<String> length = new Condition<String>(s -> s.length() > 10, "length");
		assertThat(value).matches(s -> s.length() < 12).is(length);

		String value2 = "AssertJ";
		System.out.println(value2);
		Condition<String> length2 = new Condition<String>(s -> s.length() > 6, "length");
		assertThat(value2).matches(s -> s.length() < 8).is(length2);
	}
AssertJ 155
AssertJ

Number Assertions

Fluent Assertions Java Library 驗證數字是否符合條件,若不成立,則會拋出 AssertionError 。

	@Test
	public void numberAssertions() {
		int value = 155;
		System.out.println(value);
		assertThat(value).isPositive().isGreaterThan(150).isCloseTo(150, within(5));

		double doubleValue = 151.2d;
		System.out.println(doubleValue);
		assertThat(doubleValue).isNotZero().isLessThan(152d);
	}
155
151.2

Array Assertions

Improve Unit Tests with AssertJ 驗證陣列是否符合條件,若不成立,則會拋出 AssertionError 。

	@Test
	public void arrayAssertions() {
		Fruit durian = new Fruit("Durian", Double.MAX_VALUE, 2);
		Fruit guava = new Fruit("Guava", 1, 2);
		Fruit pitaya = new Fruit("Pitaya", -1, 2);
		Fruit[] array = new Fruit[] { durian, guava, pitaya };
		System.out.println(Arrays.deepToString(array));
		assertThat(array).allMatch(e -> e.getName().length() > 4).contains(durian, guava, pitaya);
		assertThat(array).allMatch(e -> e.getType() == 2).hasSize(3);

		int[] intArray = new int[] { 1, 2, 3, 4, 5 };
		System.out.println(Arrays.toString(intArray));
		assertThat(intArray).isNotNull().containsAnyOf(1, 9).containsSequence(3, 4);
	}
[{"name":"Durian","quantity":1.7976931348623157E308,"type":2,"origins":[]}, {"name":"Guava","quantity":1.0,"type":2,"origins":[]}, {"name":"Pitaya","quantity":-1.0,"type":2,"origins":[]}]
[1, 2, 3, 4, 5]

List Assertions

Improve Unit Tests with AssertJ 驗證集合是否符合條件,若不成立,則會拋出 AssertionError 。

	@Test
	public void listAssertions() {
		List<String> list = Arrays.asList("Apple", "Banana", "Cherry");
		System.out.println(list);
		assertThat(list).isNotNull().doesNotContainNull().contains("Banana", "Apple").containsSequence("Banana",
				"Cherry");

		List<Integer> intList = Stream.of(6, 7, 8, 9, 10).collect(Collectors.toList());
		System.out.println(intList);
		Condition<Integer> intValue = new Condition<Integer>(i -> i > 0, "value");
		assertThat(intList).isNotEmpty().are(intValue);
	}
[Apple, Banana, Cherry]
[6, 7, 8, 9, 10]

Map Assertions

Improve Unit Tests with AssertJ 驗證映射是否符合條件,若不成立,則會拋出 AssertionError 。

	@Test
	public void mapAssertions() {
		Map<String, Integer> map = new HashMap<>();
		map.put("Grape", 18);
		map.put("Kiwifruit", 19);
		map.put("Lemon", 20);
		System.out.println(map);
		assertThat(map).isNotNull().containsKey("Kiwifruit").containsAnyOf(entry("Lemon", 20));
		
		Map<Integer, Integer> intMap = new HashMap<>();
		intMap.put(1, 18);
		intMap.put(2, 19);
		intMap.put(3, 20);
		System.out.println(intMap);
		assertThat(intMap).isNotEmpty().containsEntry(1, 18);
	}
{Grape=18, Kiwifruit=19, Lemon=20}
{1=18, 2=19, 3=20}

IntroductionAssertJTest.java

Improve Unit Tests with AssertJ 新增單元測試,驗證是否符合預期。

package org.ruoxue.spring_boot_168.test.assertj;

import static org.assertj.core.api.Assertions.*;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;
import org.assertj.core.api.Condition;
import org.junit.jupiter.api.Test;

import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

public class IntroductionAssertJTest {

	@NoArgsConstructor
	@Getter
	@Setter
	@Builder
	public static class Fruit {
		private String name;
		private double quantity;
		private int type;
		private List<String> origins = new ArrayList<>();

		public Fruit(String name, double quantity, int type, List<String> origins) {
			this.name = name;
			this.quantity = quantity;
			this.type = type;
			this.origins = origins;
		}

		public Fruit(String name, double quantity, int type) {
			this(name, quantity, type, new ArrayList<>());
		}

		public String toString() {
			ToStringBuilder builder = new ToStringBuilder(this, ToStringStyle.JSON_STYLE);
			builder.appendSuper(super.toString());
			builder.append("name", name);
			builder.append("quantity", quantity);
			builder.append("type", type);
			builder.append("origins", origins);
			return builder.toString();
		}
	}

	@Test
	public void booleanAssertions() {
		String value = "AssertJ";
		System.out.println(value);
		assertThat(value.startsWith("A")).isTrue();

		String value2 = "";
		System.out.println(value2);
		assertThat(value2.isEmpty()).isTrue();
	}

	@Test
	public void characterAssertions() {
		char value = 'A';
		System.out.println(value);
		assertThat(value).isNotEqualTo('a').inUnicode().isLessThanOrEqualTo('b').isUpperCase();

		char value2 = '1';
		System.out.println(value2);
		assertThat(value2).isEqualTo('1').isIn('1', '5').isGreaterThan('/');
	}

	@Test
	public void stringAssertions() {
		String value = "AssertJ 155";
		System.out.println(value);
		Condition<String> length = new Condition<String>(s -> s.length() > 10, "length");
		assertThat(value).matches(s -> s.length() < 12).is(length);

		String value2 = "AssertJ";
		System.out.println(value2);
		Condition<String> length2 = new Condition<String>(s -> s.length() > 6, "length");
		assertThat(value2).matches(s -> s.length() < 8).is(length2);
	}

	@Test
	public void numberAssertions() {
		int value = 155;
		System.out.println(value);
		assertThat(value).isPositive().isGreaterThan(150).isCloseTo(150, within(5));

		double doubleValue = 151.2d;
		System.out.println(doubleValue);
		assertThat(doubleValue).isNotZero().isLessThan(152d);
	}

	@Test
	public void arrayAssertions() {
		Fruit durian = new Fruit("Durian", Double.MAX_VALUE, 2);
		Fruit guava = new Fruit("Guava", 1, 2);
		Fruit pitaya = new Fruit("Pitaya", -1, 2);
		Fruit[] array = new Fruit[] { durian, guava, pitaya };
		System.out.println(Arrays.deepToString(array));
		assertThat(array).allMatch(e -> e.getName().length() > 4).contains(durian, guava, pitaya);
		assertThat(array).allMatch(e -> e.getType() == 2).hasSize(3);

		int[] intArray = new int[] { 1, 2, 3, 4, 5 };
		System.out.println(Arrays.toString(intArray));
		assertThat(intArray).isNotNull().containsAnyOf(1, 9).containsSequence(3, 4);
	}

	@Test
	public void listAssertions() {
		List<String> list = Arrays.asList("Apple", "Banana", "Cherry");
		System.out.println(list);
		assertThat(list).isNotNull().doesNotContainNull().contains("Banana", "Apple").containsSequence("Banana",
				"Cherry");

		List<Integer> intList = Stream.of(6, 7, 8, 9, 10).collect(Collectors.toList());
		System.out.println(intList);
		Condition<Integer> intValue = new Condition<Integer>(i -> i > 0, "value");
		assertThat(intList).isNotEmpty().are(intValue);
	}

	@Test
	public void mapAssertions() {
		Map<String, Integer> map = new HashMap<>();
		map.put("Grape", 18);
		map.put("Kiwifruit", 19);
		map.put("Lemon", 20);
		System.out.println(map);
		assertThat(map).isNotNull().containsKey("Kiwifruit").containsAnyOf(entry("Lemon", 20));
		
		Map<Integer, Integer> intMap = new HashMap<>();
		intMap.put(1, 18);
		intMap.put(2, 19);
		intMap.put(3, 20);
		System.out.println(intMap);
		assertThat(intMap).isNotEmpty().containsEntry(1, 18);
	}
}

心得分享

AssertJ Fluent Assertions for Java 支援字元、字串、數字、 Array 、 List 、 Map 等物件進行斷言,驗證是否符合條件,提供豐富的流式斷言,對於許多測試驗證的場景,可以讓開發者使用更流暢的單元測試,善用 Improve Unit Tests with AssertJ 將大幅提升驗證效率,節省不少撰寫單元測試的時間。

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