Hamcrest assertThat（）マッチャーを使用してJavaでJUnitテストケースを作成する方法–完全なチュートリアル

公開: 2022-02-05

Hamcrest for testingを使用する方法は？しばらく前に、Hello WorldJUnitの記事にすべての詳細を書きました。このチュートリアルではhow to use Hamcrest to create JUnit 。

Hamcrestは、より読みやすいJavaユニットテストを作成するためにJUnitフレームワークにバンドルされたマッチャーを備えたJavaのtesting frameworkです。私は今日それを試しました、そして私はそれを絶対に愛しています。

非常にシンプルで完全なドキュメントはそれを完璧にします。

以下の質問のいずれかがある場合は、適切な場所にいます。

Eclipseを使用してJavaでJUnitテストケースを作成する
Javaでjunitテストケースを作成する方法
JavaでのサンプルJUnitテストケース
Hamcrest Matchersを使用したJUnitテストケースの作成
JUnitテストでのassertThat vs Assertメソッドの利点
hamcrest assertthat()チュートリアル
Hamcrestを使用したテスト

始めましょう：

EclipseでJavaクラスCrunchifyHemcrestJUnitTest.javaを作成します。 4つの異なるカテゴリのテストを作成します。

Java List用のJUnitテストケースを作成する
JavaMap用のJUnitテストケースを作成する
JavaオブジェクトのJUnitテストケースを作成する
ヌルチェック用のJUnitテストケースを作成する

ハムクレストのトップマッチャーは次のとおりです。

は（）
hasItems（）
hasSize（）
contains（）
containsInAnyOrder（）

以下のチュートリアルでは、常に合格するほぼすべてのマッチャーテストケースについて説明します。誤検知などを作成するように変更するだけです。

プロジェクトに以下のMaven依存関係を追加する必要があります。

< dependency >

< groupId > org . hamcrest < / groupId >

< artifactId > hamcrest - all < / artifactId >

< version > 1.3 < / version >

< / dependency >

これをpom.xmlファイルに追加するだけです。 pom.xmlが表示されない場合は、このチュートリアルに従ってください。

containsinanyorder-hamcrest-java-junit-test

これが完全なJavaコードです

クラスを右クリックして、「 Run As 」->「 JUnit Test 」を選択します。

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 ~~~~~~~~~~~" ) ;

}

Eclipseコンソール出力：

上記のプログラムをJavaアプリケーションとして実行するだけで、次のような結果が表示されます。

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 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

上記のプログラムの実行中に問題が発生した場合はお知らせください。