Package org.instancio.junit

Interface GivenProvider

@ExperimentalApi
public interface GivenProvider

An interface for providing instances of objects that can be injected into fields or parameters using the @Given annotation.

For example, we may want to define a custom annotation for generating numeric strings:

 @ExtendWith(InstancioExtension.class)
 class ExampleTest {

     @Test
     void example(@NumericString(length = 5) String digits) {
         // Possible value of digits: 04194
     }
 }
 

To support the above use case, first we define the @NumericString annotation:

 @Given(NumericStringProvider.class)
 @Target({ElementType.FIELD, ElementType.PARAMETER})
 @Retention(RetentionPolicy.RUNTIME)
 @interface NumericString {
     int length();
 }
 

where the NumericStringProvider can be implemented as:

 class NumericStringProvider implements GivenProvider {
     @Override
     public Object provide(ElementContext context) {
         NumericString numericString = context.getAnnotation(NumericString.class);
         return context.random().digits(numericString.length());
     }
 }
 

Since:

5.0.0

See Also:

• Given

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	GivenProvider.ElementContext	An interface representing the context of an element (either a Field or Parameter) for which an object instance is being provided.

Method Summary

Modifier and Type	Method	Description
Object	provide(GivenProvider.ElementContext context)	Provides an instance of an object based on the given context.

Method Details

provide

@ExperimentalApi
Object provide(GivenProvider.ElementContext context)

Provides an instance of an object based on the given context.

Parameters:

context - the context containing metadata about the element (either a Field or Parameter) annotated or meta-annotated with the @Given annotation

Returns:

an instance of an object

Since:

5.0.0