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:

Java
Kotlin

assertThat(mockMvc.get().uri("/hotels/{id}", 42))
		.hasStatusOk()
		.hasContentTypeCompatibleWith(MediaType.APPLICATION_JSON)
		.bodyJson().isLenientlyEqualTo("sample/hotel-42.json");

assertThat(mockMvc.get().uri("/hotels/{id}", 42))
	.hasStatusOk()
	.hasContentTypeCompatibleWith(MediaType.APPLICATION_JSON)
	.bodyJson().isLenientlyEqualTo("sample/hotel-42.json")

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

Java
Kotlin

assertThat(mockMvc.get().uri("/hotels/{id}", -1))
		.hasFailed()
		.hasStatus(HttpStatus.BAD_REQUEST)
		.failure().hasMessageContaining("Identifier should be positive");

assertThat(mockMvc.get().uri("/hotels/{id}", -1))
	.hasFailed()
	.hasStatus(HttpStatus.BAD_REQUEST)
	.failure().hasMessageContaining("Identifier should be positive")

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.

JSON Support

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

If 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:

Java
Kotlin

assertThat(mockMvc.get().uri("/family")).bodyJson()
		.extractingPath("$.members[0]")
		.asMap()
		.contains(entry("name", "Homer"));

assertThat(mockMvc.get().uri("/family")).bodyJson()
	.extractingPath("$.members[0]")
	.asMap()
	.contains(entry("name", "Homer"))

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

Java
Kotlin

assertThat(mockMvc.get().uri("/family")).bodyJson()
		.extractingPath("$.members[0]")
		.convertTo(Member.class)
		.satisfies(member -> assertThat(member.name).isEqualTo("Homer"));

assertThat(mockMvc.get().uri("/family")).bodyJson()
	.extractingPath("$.members[0]")
	.convertTo(Member::class.java)
	.satisfies(ThrowingConsumer { member: Member ->
		assertThat(member.name).isEqualTo("Homer")
	})

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:

Java
Kotlin

assertThat(mockMvc.get().uri("/family")).bodyJson()
		.extractingPath("$.members")
		.convertTo(InstanceOfAssertFactories.list(Member.class))
		.hasSize(5)
		.element(0).satisfies(member -> assertThat(member.name).isEqualTo("Homer"));

assertThat(mockMvc.get().uri("/family")).bodyJson()
	.extractingPath("$.members")
	.convertTo(InstanceOfAssertFactories.list(Member::class.java))
	.hasSize(5)
	.element(0).satisfies(ThrowingConsumer { member: Member ->
		assertThat(member.name).isEqualTo("Homer")
	})

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:

Java
Kotlin

assertThat(mockMvc.get().uri("/family")).bodyJson()
		.isStrictlyEqualTo("sample/simpsons.json");

assertThat(mockMvc.get().uri("/family")).bodyJson()
	.isStrictlyEqualTo("sample/simpsons.json")

If you prefer to use another library, you can provide an implementation of JsonComparator.