Create a JsonProcessingException

Question

I'm trying to create a JsonProcessingException to be thrown by a mock object.

when(mapper.writeValueAsString(any(Object.class))).thenThrow(new JsonProcessingException("Error"));

However I'm unable to create a JsonProcessingException object as all the constructors are protected. How do I get around this?

Answer 1

how about you create an anonymous exception of type JsonProcessingException

when(mapper.writeValueAsString(any(Object.class))).thenThrow(new JsonProcessingException("Error"){});

The {} braces does the trick. This is much better since it is not confusing to the reader of the test code.

Answer 2

How about throwing one of the known direct subclasses instead?

for v1.0

Direct Known Subclasses:
JsonGenerationException, JsonMappingException, JsonParseException

for v2.0

Direct Known Subclasses:
JsonGenerationException, JsonParseException

Answer 3

This one worked for me which allowed to throw JsonProcessingException itself

doThrow(JsonProcessingException.class).when(mockedObjectMapper).writeValueAsString(Mockito.any());

Answer 4

I came across this issue today also. The simplest and cleanest solution I came up with was to create and throw a mock JsonProcessingException

when(mapper.writeValueAsString(any(Object.class)))
    .thenThrow(mock(JsonProcessingException.class));

Answer 5

Faced the same issue today. You can use:

Mockito.when(mockObjectMapper.writeValueAsString(Mockito.any())).thenThrow(JsonProcessingException.class);