Class ArgumentCaptor<T>
- java.lang.Object
-
- org.mockito.ArgumentCaptor<T>
-
public class ArgumentCaptor<T> extends Object
Use it to capture argument values for further assertions.Mockito verifies argument values in natural java style: by using an equals() method. This is also the recommended way of matching arguments because it makes tests clean and simple. In some situations though, it is helpful to assert on certain arguments after the actual verification. For example:
Example of capturing varargs:ArgumentCaptor<Person> argument = ArgumentCaptor.forClass(Person.class); verify(mock).doSomething(argument.capture()); assertEquals("John", argument.getValue().getName());
//capturing varargs: ArgumentCaptor<Person> varArgs = ArgumentCaptor.forClass(Person.class); verify(mock).varArgMethod(varArgs.capture()); List expected = asList(new Person("John"), new Person("Jane")); assertEquals(expected, varArgs.getAllValues());
Warning: it is recommended to use ArgumentCaptor with verification but not with stubbing. Using ArgumentCaptor with stubbing may decrease test readability because captor is created outside of assertion (aka verify or 'then') blocks. It may also reduce defect localization because if the stubbed method was not called, then no argument is captured.
In a way ArgumentCaptor is related to custom argument matchers (see javadoc for
ArgumentMatcher
class). Both techniques can be used for making sure certain arguments were passed to mock objects. However, ArgumentCaptor may be a better fit if:- custom argument matcher is not likely to be reused
- you just need it to assert on argument values to complete verification
ArgumentMatcher
are usually better for stubbing.This utility class *doesn't do any type checks*. The generic signatures are only there to avoid casting in your code.
There is an annotation that you might find useful: @
Captor
See the full documentation on Mockito in javadoc for
Mockito
class.- Since:
- 1.8.0
- See Also:
Captor
-
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description T
capture()
Use it to capture the argument.static <U,S extends U>
ArgumentCaptor<U>forClass(Class<S> clazz)
Build a newArgumentCaptor
.List<T>
getAllValues()
Returns all captured values.T
getValue()
Returns the captured value of the argument.
-
-
-
Method Detail
-
capture
public T capture()
Use it to capture the argument. This method must be used inside of verification.Internally, this method registers a special implementation of an
ArgumentMatcher
. This argument matcher stores the argument value so that you can use it later to perform assertions.See examples in javadoc for
ArgumentCaptor
class.- Returns:
- null or default values
-
getValue
public T getValue()
Returns the captured value of the argument. When capturing varargs usegetAllValues()
.If verified method was called multiple times then this method it returns the latest captured value.
See examples in javadoc for
ArgumentCaptor
class.- Returns:
- captured argument value
-
getAllValues
public List<T> getAllValues()
Returns all captured values. Use it when capturing varargs or when the verified method was called multiple times. When varargs method was called multiple times, this method returns merged list of all values from all invocations.Example:
Example of capturing varargs:mock.doSomething(new Person("John"); mock.doSomething(new Person("Jane"); ArgumentCaptor<Person> peopleCaptor = ArgumentCaptor.forClass(Person.class); verify(mock, times(2)).doSomething(peopleCaptor.capture()); List<Person> capturedPeople = peopleCaptor.getAllValues(); assertEquals("John", capturedPeople.get(0).getName()); assertEquals("Jane", capturedPeople.get(1).getName());
See more examples in javadoc formock.countPeople(new Person("John"), new Person("Jane"); //vararg method ArgumentCaptor<Person> peopleCaptor = ArgumentCaptor.forClass(Person.class); verify(mock).countPeople(peopleCaptor.capture()); List expected = asList(new Person("John"), new Person("Jane")); assertEquals(expected, peopleCaptor.getAllValues());
ArgumentCaptor
class.- Returns:
- captured argument value
-
forClass
public static <U,S extends U> ArgumentCaptor<U> forClass(Class<S> clazz)
Build a newArgumentCaptor
.Note that an
ArgumentCaptor
*doesn't do any type checks*. It is only there to avoid casting in your code. This might however change (type checks could be added) in a future major release.- Type Parameters:
S
- Type of clazzU
- Type of object captured by the newly built ArgumentCaptor- Parameters:
clazz
- Type matching the parameter to be captured.- Returns:
- A new ArgumentCaptor
-
-