Java에서 JUnit 테스트 케이스를 생성하기 위해 Hamcrest assertThat() Matchers를 사용하는 방법 – 튜토리얼 완료

게시 됨: 2022-02-05

Hamcrest for testing 를 사용하는 방법은 무엇입니까? 언젠가 나는 모든 세부 사항이 포함된 Hello World JUnit 기사를 작성했습니다. 이 자습서에서는 how to use Hamcrest to create JUnit 에 대한 단계를 살펴보겠습니다.

Hamcrest는 더 읽기 쉬운 Java 단위 테스트를 생성하기 위해 JUnit 프레임워크와 함께 번들로 제공되는 매처가 있는 Java용 testing framework 입니다. 나는 오늘 그것을 시도했고 나는 그것을 절대적으로 좋아합니다.

매우 간단하고 완전한 문서로 완벽합니다.

아래 질문 중 하나가 있으면 올바른 위치에 있습니다.

Eclipse를 사용하여 Java로 JUnit 테스트 케이스 작성
Java에서 junit 테스트 케이스를 작성하는 방법
Java의 샘플 JUnit 테스트 케이스
Hamcrest Matchers 를 사용하여 JUnit 테스트 케이스 작성
JUnit 테스트에서 assertThat vs Assert 메소드의 이점
hamcrest assertthat() 튜토리얼
Hamcrest로 테스트

시작하자:

Eclipse에서 Java 클래스 CrunchifyHemcrestJUnitTest.java 를 만듭니다. 4가지 다른 범주의 테스트를 만들 것입니다.

Java List 에 대한 JUnit 테스트 케이스 생성
Java Map용 JUnit 테스트 케이스 생성
Java 객체용 JUnit 테스트 케이스 생성
Null 검사를 위한 JUnit 테스트 케이스 생성

최고의 Hamcrest 매처는 다음과 같습니다.

이다()
hasItems()
hasSize()
포함()
포함된AnyOrder()

아래 튜토리얼은 항상 통과할 거의 모든 matchers 테스트 케이스를 다룹니다. 가양성 등을 생성하도록 수정하기만 하면 됩니다.

프로젝트에 아래 maven 종속성을 추가해야 합니다.

< dependency >

< groupId > org . hamcrest < / groupId >

< artifactId > hamcrest - all < / artifactId >

< version > 1.3 < / version >

< / dependency >

이것을 pom.xml 파일에 추가하기만 하면 됩니다. pom.xml이 표시되지 않으면 이 자습서를 따르십시오.

다음은 완전한 Java 코드입니다.

클래스를 마우스 오른쪽 버튼으로 클릭하고 Run As -> JUnit Test .

CrunchifyHamcrestJUnitTest.java

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package crunchify . com . java . tutorials ;

import org . hamcrest . collection . IsEmptyCollection ;

import org . hamcrest . collection . IsMapContaining ;

import org . hamcrest . core . IsNull ;

import org . junit . Test ;

import java . util . * ;

import static org . hamcrest . CoreMatchers . * ;

import static org . hamcrest . MatcherAssert . assertThat ;

import static org . hamcrest . Matchers . hasProperty ;

import static org . hamcrest . collection . IsCollectionWithSize . hasSize ;

import static org . hamcrest . collection . IsIterableContainingInAnyOrder . containsInAnyOrder ;

import static org . hamcrest . collection . IsIterableContainingInOrder . contains ;

/**

* @author Crunchify.com

* <p>

* Hamcrest JUnit Tutorials by Crunchify.com

* 1. Create JUnit testcases for Java List

* 2. Create JUnit testcases for Java Map

* 3. Create JUnit testcases for Java Object

* 4. Create JUnit testcases for Null Check

public class CrunchifyHamcrestJUnitTest {

// Testcase-1: JUnit for List

@Test

public void crunchifyListJUnitTests ( ) {

// List: An ordered collection (also known as a sequence). The user of this interface has precise control over where in the list each element is inserted.

// The user can access elements by their integer index (position in the list), and search for elements in the list.

List <String> company = Arrays . asList ( "Crunchify.com" , "Google.com" , "Facebook.com" ) ;

// asList(): Returns a fixed-size list backed by the specified array. Changes made to the array will be visible in the returned list,

// and changes made to the list will be visible in the array.

// The returned list is Serializable and implements RandomAccess.

List <String> crunchifyCompany = Arrays . asList ( "Crunchify.com" , "Google.com" , "Facebook.com" ) ;

crunchifyLog ( "\n~~~~~~~~~~~JUnit List Check Test~~~~~~~~~~~" ) ;

crunchifyLog ( "1) assertThat(company, is(crunchifyCompany)) check" ) ;

// A shortcut to the frequently used is(equalTo(x)).

assertThat ( company , is ( crunchifyCompany ) ) ;

crunchifyLog ( "2) .hasItems() check" ) ;

assertThat ( company , hasItems ( "Crunchify.com" ) ) ;

crunchifyLog ( "3) .hasSize() check" ) ;

assertThat ( company , hasSize ( 3 ) ) ;

assertThat ( company . size ( ) , is ( 3 ) ) ;

crunchifyLog ( "4) .contains() and .containsInAnyOrder() check" ) ;

assertThat ( company , contains ( "Crunchify.com" , "Google.com" , "Facebook.com" ) ) ;

assertThat ( company , containsInAnyOrder ( "Google.com" , "Crunchify.com" , "Facebook.com" ) ) ;

// FAIL

// assertThat(company, contains("Google.com", "Crunchify.com", "Facebook.com"));

crunchifyLog ( "5) .empty() check" ) ;

assertThat ( company , not ( IsEmptyCollection . empty ( ) ) ) ;

assertThat ( new ArrayList < > ( ) , IsEmptyCollection . empty ( ) ) ;

}

private void crunchifyLog ( String crunchifyText ) {

System . out . println ( crunchifyText ) ;

}

@Test

public void crunchifyMapJUnitTests ( ) {

Map < String , String > company = new HashMap < > ( ) ;

company . put ( "C" , "Crunchify.com" ) ;

company . put ( "G" , "Google.com" ) ;

company . put ( "F" , "Facebook.com" ) ;

// Map: An object that maps keys to values. A map cannot contain duplicate keys; each key can map to at most one value.

// This interface takes the place of the Dictionary class, which was a totally abstract class rather than an interface.

Map < String , String > crunchifyCompany = new HashMap < > ( ) ;

crunchifyCompany . put ( "C" , "Crunchify.com" ) ;

// put(): Associates the specified value with the specified key in this map (optional operation).

// If the map previously contained a mapping for the key, the old value is replaced by the specified value.

// (A map m is said to contain a mapping for a key k if and only if m.containsKey(k) would return true.)

crunchifyCompany . put ( "G" , "Google.com" ) ;

crunchifyCompany . put ( "F" , "Facebook.com" ) ;

crunchifyLog ( "\n~~~~~~~~~~~ JUnit Map Check Test - All tests will PASS in our example ~~~~~~~~~~~" ) ;

crunchifyLog ( "1) assertThat(company, is(crunchifyCompany) check" ) ;

assertThat ( company , is ( crunchifyCompany ) ) ;

crunchifyLog ( "2) assertThat(company.size(), is(3)) check" ) ;

assertThat ( company . size ( ) , is ( 3 ) ) ;

crunchifyLog ( "3) .hasEntry() check which creates a matcher for Maps matching at least one entry whose key equals the specified key & value." ) ;

assertThat ( company , IsMapContaining . hasEntry ( "C" , "Crunchify.com" ) ) ;

assertThat ( company , not ( IsMapContaining . hasEntry ( "G" , "Twitter.com" ) ) ) ;

crunchifyLog ( "4) .hasKey() creates a matcher for Maps matching at least one key that is equal to the specified key." ) ;

assertThat ( company , IsMapContaining . hasKey ( "F" ) ) ;

crunchifyLog ( "5) .hasValue() creates a matcher for Maps matching at least one key that is equal to the specified value." ) ;

assertThat ( company , IsMapContaining . hasValue ( "Crunchify.com" ) ) ;

}

@SuppressWarnings ( "unchecked" )

@Test

public void crunchifyObjectJUnitTests ( ) {

List <Company> list = Arrays . asList ( new Company ( "Crunchify" , 10 ) , new Company ( "Google" , 30000 ) ) ;

assertThat ( list , hasItems ( new Company ( "Crunchify" , 10 ) , new Company ( "Google" , 30000 ) ) ) ;

assertThat ( list , containsInAnyOrder ( new Company ( "Google" , 30000 ) , new Company ( "Crunchify" , 10 ) ) ) ;

assertThat ( list , containsInAnyOrder ( hasProperty ( "name" , is ( "Google" ) ) , hasProperty ( "name" , is ( "Crunchify" ) ) ) ) ;

crunchifyLog ( "\n~~~~~~~~~~~ JUnit Object Check Test Completed ~~~~~~~~~~~" ) ;

}

// Create Company Object

public static class Company {

public Company ( String name , int employeeCount ) {

this . name = name ;

this . employeeCount = employeeCount ;

}

private String name ;

private int employeeCount ;

public int getEmployeeCount ( ) {

return employeeCount ;

}

public void setEmployeeCount ( int employeeCount ) {

this . employeeCount = employeeCount ;

}

public String getName ( ) {

return name ;

}

public void setName ( String name ) {

this . name = name ;

}

// Test equal, override equals() and hashCode()

@Override

public boolean equals ( Object c ) {

if ( this == c )

return true ;

if ( c == null | | getClass ( ) ! = c . getClass ( ) )

return false ;

Company fruit = ( Company ) c ;

return employeeCount == fruit . employeeCount && Objects.equals(name, fruit.name);

}

@Override

public int hashCode ( ) {

return Objects . hash ( name , employeeCount ) ;

}

@Test

public void crunchifyNullCheckJUnitTest ( ) {

// Two ways to check isNull

assertThat ( null , is ( nullValue ( ) ) ) ;

assertThat ( null , is ( IsNull . nullValue ( ) ) ) ;

// Two ways to check isNotNull

assertThat ( "crunchify" , is ( notNullValue ( ) ) ) ;

assertThat ( "crunchify" , is ( IsNull . notNullValue ( ) ) ) ;

crunchifyLog ( "\n~~~~~~~~~~~ JUnit Null Check Test Completed ~~~~~~~~~~~" ) ;

}

이클립스 콘솔 출력:

위의 프로그램을 Java Application으로 실행하면 아래와 같은 결과를 볼 수 있습니다.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit Object Check Test Completed ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit Null Check Test Completed ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit List Check Test ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

1 ) assertThat ( company , is ( crunchifyCompany ) ) check

2 ) . hasItems ( ) check

3 ) . hasSize ( ) check

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit List Check Test ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

1 ) assertThat ( company , is ( crunchifyCompany ) ) check

2 ) . hasItems ( ) check

3 ) . hasSize ( ) check

4 ) . contains ( ) and . containsInAnyOrder ( ) check

5 ) . empty ( ) check

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit Map Check Test - All tests will PASS in our example ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

1 ) assertThat ( company , is ( crunchifyCompany ) check

2 ) assertThat ( company . size ( ) , is ( 3 ) ) check

3 ) . hasEntry ( ) check which creates a matcher for Maps matching at least one entry whose key equals the specified key & value .

4 ) . hasKey ( ) creates a matcher for Maps matching at least one key that is equal to the specified key .

5 ) . hasValue ( ) creates a matcher for Maps matching at least one key that is equal to the specified value .

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit Object Check Test Completed ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ JUnit Null Check Test Completed ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Process finished with exit code 0

위 프로그램을 실행하는 데 문제가 있으면 알려주십시오.