Comment utiliser Hamcrest assertThat () Matchers pour créer des cas de test JUnit en Java - Tutoriel complet

Publié: 2022-02-05
Comment utiliser Hamcrest assertThat () Matchers pour créer des cas de test JUnit en Java

Comment utiliser Hamcrest for testing ? Il y a quelque temps, j'ai écrit un article Hello World JUnit avec tous les détails. Dans ce didacticiel, nous passerons en revue les étapes how to use Hamcrest to create JUnit pour votre projet Java.

Hamcrest est un testing framework pour Java avec des matchers fournis avec le framework JUnit pour créer des tests unitaires Java plus lisibles. Je l'ai essayé aujourd'hui et je l'adore.

Une documentation très simple et complète le rend parfait.

Si vous avez l'une des questions ci-dessous, vous êtes au bon endroit :

  • Rédaction de cas de test JUnit en Java avec Eclipse
  • Comment écrire des cas de test Junit en Java
  • Exemples de cas de test JUnit en Java
  • Rédaction de cas de test JUnit à l'aide Hamcrest Matchers
  • Les avantages des assertThat vs Assert dans les tests JUnit
  • tuto hamcrest assertthat()
  • Tester avec Hamcrest

Commençons:

Créez la classe Java CrunchifyHemcrestJUnitTest.java dans Eclipse. Nous allons créer 4 catégories différentes de tests.

  1. Créer des cas de test JUnit pour Java List
  2. Créer des cas de test JUnit pour Java Map
  3. Créer des cas de test JUnit pour Java Object
  4. Créer des cas de test JUnit pour Null Check

Voici les meilleurs matchers Hamcrest:

  • est()
  • a des éléments ()
  • aTaille()
  • contient()
  • contientDansAnyOrder()

Le didacticiel ci-dessous couvre presque tous les cas de test de matchers qui passeront tout le temps. Modifiez simplement pour créer un faux positif, etc.

Vous devez ajouter ci-dessous la dépendance maven dans votre projet.

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< dependency >
< groupId > org . hamcrest < / groupId >
< artifactId > hamcrest - all < / artifactId >
< version > 1.3 < / version >
< / dependency >

Ajoutez simplement ceci au fichier pom.xml . Si vous ne voyez pas pom.xml, suivez ce tutoriel.

contient dans n'importe quel ordre-hamcrest-java-junit-test

Voici un code Java complet

Cliquez simplement avec le bouton droit sur une classe et Run As -> JUnit Test .

CrunchifyHamcrestJUnitTest.java

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

Sortie console Eclipse :

Exécutez simplement le programme ci-dessus en tant qu'application Java et vous devriez voir le résultat comme ci-dessous.

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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 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
résultat du test hamcrest-java-junit

Faites-nous savoir si vous rencontrez un problème lors de l'exécution du programme ci-dessus.