[[mockmvc-tester-assertions]]
= Defining Expectations

Assertions work the same way as any AssertJ assertions. The support provides dedicated
assert objects for the various pieces of the `MvcTestResult`, as shown in the following
example:

include-code::./HotelControllerTests[tag=get,indent=0]

If a request fails, the exchange does not throw the exception. Rather, you can assert
that the result of the exchange has failed:

include-code::./HotelControllerTests[tag=failure,indent=0]

The request could also fail unexpectedly, that is the exception thrown by the handler
has not been handled and is thrown as is. You can still use `.hasFailed()` and
`.failure()` but any attempt to access part of the result will throw an exception as
the exchange hasn't completed.


[[mockmvc-tester-assertions-json]]
== JSON Support

The AssertJ support for `MvcTestResult` provides JSON support via `bodyJson()`.

If https://github.com/jayway/JsonPath[JSONPath] is available, you can apply an expression
on the JSON document. The returned value provides convenient methods to return a dedicated
assert object for the various supported JSON data types:

include-code::./FamilyControllerTests[tag=extract-asmap,indent=0]

You can also convert the raw content to any of your data types as long as the message
converter is configured properly:

include-code::./FamilyControllerTests[tag=extract-convert,indent=0]

Converting to a target `Class` provides a generic assert object. For more complex types,
you may want to use `AssertFactory` instead that returns a dedicated assert type, if
possible:

include-code::./FamilyControllerTests[tag=extract-convert-assert-factory,indent=0]

https://jsonassert.skyscreamer.org[JSONAssert] is also supported. The body of the
response can be matched against a `Resource` or a content. If the content ends with
`.json ` we look for a file matching that name on the classpath:

include-code::./FamilyControllerTests[tag=assert-file,indent=0]

If you prefer to use another library, you can provide an implementation of
{spring-framework-api}/test/json/JsonComparator.html[`JsonComparator`].
