Table of Contents
ToggleAssertJ Java 8 Features
介紹 AssertJ 的 Java 8 相關功能,為 Java 8 類型提供特殊的輔助方法,及新斷言使用 Java 8 功能,通過 Java 8 Features AssertJ 流式斷言,可以大幅提升斷言效率,減少程式碼的撰寫,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
| +- AssertJJava8FeaturesTest.java
Dependencies
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。
Java 7 或是更早之前的版本,則須引用 AssertJ 2.x.x。
Gradle
build.gradle
dependencies {
testImplementation "org.assertj:assertj-core:3.23.1"
}
Maven
pom.xml
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>3.23.1</version>
<scope>test</scope>
</dependency>
單元測試
Assertions Java 8 Features 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();
}
}
Optional Assertions
驗證 Optional 容器內值是否存在,若不成立,則會拋出 AssertionError 。
@Test
public void optionalAssertions() {
Optional<String> value = Optional.of("AssertJ");
System.out.println(value);
assertThat(value).isPresent();
Optional<Integer> intValue = Optional.of(155);
System.out.println(intValue);
assertThat(intValue).isPresent();
}
Optional[AssertJ]
Optional[155]
Predicate Assertions
Assertions Java 8 Features 驗證是否符合條件,若不成立,則會拋出 AssertionError 。
@Test
public void predicateAssertions() {
Predicate<String> lengthGreaterThan = s -> s.length() > 3;
System.out.println(lengthGreaterThan);
assertThat(lengthGreaterThan).accepts("AssertJ", "JUnit");
Predicate<Integer> greaterThan = i -> i > 10;
System.out.println(greaterThan);
assertThat(greaterThan).accepts(155, 151);
}
org.ruoxue.spring_boot_168.test.assertj.AssertJJava8FeaturesTest$$Lambda$277/1975546571@1f1c7bf6
org.ruoxue.spring_boot_168.test.assertj.AssertJJava8FeaturesTest$$Lambda$282/2021707251@5be6e01c
LocalDateTime Assertions
Assertions Java 8 Features 驗證日期時間是否在指定日期時間之前,若不成立,則會拋出 AssertionError 。
@Test
public void localDateAssertions() {
LocalDateTime value = LocalDateTime.of(2023, 10, 31, 5, 6, 7);
System.out.println(value);
assertThat(value).isBefore(LocalDateTime.of(2023, 10, 31, 5, 6, 12));
assertThat(value).isBefore(LocalDateTime.of(2023, 10, 31, 5, 7, 7));
}
2023-10-31T05:06:07
FlatExtracting
Assertions Java 8 Features 驗證取得根據類名或方法引用或屬性名反射調用,或根據 lambda 表達式調用,提取元素屬性符合條件,若不成立,則會拋出 AssertionError 。
@Test
public void flatExtracting() {
Fruit apple = new Fruit("Apple", Double.MAX_VALUE, 1, Arrays.asList("Australia"));
Fruit banana = new Fruit("Banana", 1, 2, Arrays.asList("Canada", "Norway"));
Fruit cherry = new Fruit("Cherry", -1, 3, Arrays.asList("Poland", "Japan"));
List<Fruit> list = Arrays.asList(apple, banana, cherry);
System.out.println(list);
assertThat(list).flatExtracting("origins").containsOnly("Australia", "Canada", "Norway", "Poland", "Japan");
}
[{"name":"Apple","quantity":1.7976931348623157E308,"type":1,"origins":[Australia]}, {"name":"Banana","quantity":1.0,"type":2,"origins":[Canada, Norway]}, {"name":"Cherry","quantity":-1.0,"type":3,"origins":[Poland, Japan]}]
Satisfies
Asserting Java 8 Features 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).isNotEmpty();
assertThat(s).hasSize(11);
});
int intValue = 155;
System.out.println(intValue);
assertThat(intValue).satisfies(i -> {
assertThat(i).isNotZero();
assertThat(i).isLessThan(156);
});
}
AssertJ 155
155
Matches
Asserting Java 8 Features with Examples 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);
int intValue = 155;
System.out.println(intValue);
assertThat(intValue).matches(i -> i < 156);
}
AssertJ 155
155
AssertJJava8FeaturesTest.java
Asserting Java 8 Features with Examples 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.assertThat;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.function.Predicate;
import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;
import org.junit.jupiter.api.Test;
import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
public class AssertJJava8FeaturesTest {
@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 optionalAssertions() {
Optional<String> value = Optional.of("AssertJ");
System.out.println(value);
assertThat(value).isPresent();
Optional<Integer> intValue = Optional.of(155);
System.out.println(intValue);
assertThat(intValue).isPresent();
}
@Test
public void predicateAssertions() {
Predicate<String> lengthGreaterThan = s -> s.length() > 3;
System.out.println(lengthGreaterThan);
assertThat(lengthGreaterThan).accepts("AssertJ", "JUnit");
Predicate<Integer> greaterThan = i -> i > 10;
System.out.println(greaterThan);
assertThat(greaterThan).accepts(155, 151);
}
@Test
public void localDateAssertions() {
LocalDateTime value = LocalDateTime.of(2023, 10, 31, 5, 6, 7);
System.out.println(value);
assertThat(value).isBefore(LocalDateTime.of(2023, 10, 31, 5, 6, 12));
assertThat(value).isBefore(LocalDateTime.of(2023, 10, 31, 5, 7, 7));
}
@Test
public void flatExtracting() {
Fruit apple = new Fruit("Apple", Double.MAX_VALUE, 1, Arrays.asList("Australia"));
Fruit banana = new Fruit("Banana", 1, 2, Arrays.asList("Canada", "Norway"));
Fruit cherry = new Fruit("Cherry", -1, 3, Arrays.asList("Poland", "Japan"));
List<Fruit> list = Arrays.asList(apple, banana, cherry);
System.out.println(list);
assertThat(list).flatExtracting("origins").containsOnly("Australia", "Canada", "Norway", "Poland", "Japan");
}
@Test
public void satisfies() {
String value = "AssertJ 155";
System.out.println(value);
assertThat(value).satisfies(s -> {
assertThat(s).isNotEmpty();
assertThat(s).hasSize(11);
});
int intValue = 155;
System.out.println(intValue);
assertThat(intValue).satisfies(i -> {
assertThat(i).isNotZero();
assertThat(i).isLessThan(156);
});
}
@Test
public void matches() {
String value = "AssertJ 155";
System.out.println(value);
assertThat(value).matches(s -> s.length() < 12);
int intValue = 155;
System.out.println(intValue);
assertThat(intValue).matches(i -> i < 156);
}
}
心得分享
Testing Java 8 with AssertJ 提供 Java 8 的新特色,像是 Optional 、 Predicate 、 LocalDateTime 等物件及 flatExtracting 、 satisfies 、 matches 輔助方法,進行斷言,驗證是否成立,在許多測試驗證的場景,讓開發者使用更流暢的單元測試,善用 Asserting Java 8 Features with Examples 將有助於驗證效率的提升。