Introduce additional JsonPath matchers in Spring MVC Test [SPR-13320]

[spring-projects-issues]

Martin Meyer opened SPR-13320 and commented

Status Quo

JsonPathResultMatchers currently has the following ResultMatcher methods.

• value(Object)
• value(Matcher)
• doesNotExist()
• exists()
• isArray()

Proposal

It would be beneficial to introduce the following.

• isBoolean()
• isNumber()
• isObject()
• isString()

---

Affects: 3.2 GA

Issue Links:

• JsonPath assertions fail to differentiate between definite and indefinite results in checks for existence [SPR-13351] #17935 JsonPath assertions fail to differentiate between definite and indefinite results in checks for existence
• Introduce JsonPath matchers for empty and non-empty content [SPR-13352] #17936 Introduce JsonPath matchers for empty and non-empty content

Referenced from: pull request #854

[spring-projects-issues]

Craig commented

Looks like these are the files that would change:

• https://github.com/spring-projects/spring-framework/blob/v4.2.0.RELEASE/spring-test/src/main/java/org/springframework/test/web/servlet/result/JsonPathResultMatchers.java
• https://github.com/spring-projects/spring-framework/blob/v4.2.0.RELEASE/spring-test/src/test/java/org/springframework/test/web/servlet/result/JsonPathResultMatchersTests.java

[spring-projects-issues]

Craig commented

isObject doesn't make too much sense to me as the test would actually be for a Map... I suppose this difference is one of the confusing ways in which loosely typed Javascript/JSON differs from strongly typed Java. Since it made more sense to me, I named the method "isMap"

Here's a pull request resolving this issue:
#854

[spring-projects-issues]

Sam Brannen commented

Completed in GitHub commit 35dd307:

Introduce additional JsonPath matchers in Spring MVC Test

This commit introduces the following methods in JsonPathResultMatchers in the Spring MVC Test framework.

• isString()
• isBoolean()
• isNumber()
• isMap()

In addition, this commit overhauls the Javadoc in JsonPathResultMatchers and JsonPathExpectationsHelper.

[spring-projects-issues]

Stéphane Nicoll commented

This actually broke Spring Boot.

in JsonPathExpectationsHelper there is an assertion that checks that if the result is a list, then it shouldn't be empty.

JSONArray implements list for some reason and the following test in Boot now fails.

@Test
public void trace() throws Exception {
	this.mockMvc
			.perform(get("/trace").accept(MediaType.APPLICATION_JSON))
			.andExpect(status().isOk())
			.andExpect(jsonPath("$._links.self.href").value("http://localhost/trace"))
			.andExpect(jsonPath("$.content").isArray());
}

jsonPath("$.content").isArray() fails as follow

No value for JSON path "$.content"

	at org.springframework.test.util.AssertionErrors.fail(AssertionErrors.java:39)
	at org.springframework.test.util.AssertionErrors.assertTrue(AssertionErrors.java:72)
	at org.springframework.test.util.JsonPathExpectationsHelper.assertExistsAndReturn(JsonPathExpectationsHelper.java:242)

FYI, the output of the service is the following

{"content":[],"_links":{"self":{"href":"http://localhost/trace","templated":false}}}

Sam, this prevents us from upgrading to Spring Framework 4.2.1 snapshots.

[spring-projects-issues]

Sam Brannen commented

Revised in additional GitHub commit 5a05cdb:

Consider empty arrays as existent in JsonPath assertions

Prior to this commit, a JsonPath assertion that a path expression evaluated to an array in JsonPathExpectationsHelper (and therefore indirectly in JsonPathResultMatchers in Spring MVC Test) would incorrectly fail if the array was present in the JSON content but empty.

This commit fixes this issue by removing the "not empty" check for arrays and lists.

[spring-projects-issues]

Sam Brannen commented

If you're following this issue, you will likely be interested in the following issues as well.

• JsonPath assertions fail to differentiate between definite and indefinite results in checks for existence [SPR-13351] #17935
• Introduce JsonPath matchers for empty and non-empty content [SPR-13352] #17936

[spring-projects-issues]

Sam Brannen commented

Additional work performed in GitHub commit 4799668:

Introduce additional JsonPath RequestMatchers in Spring MVC Test

Commit fffdd1e introduced additional JsonPath result matchers in JsonPathResultMatchers for server-side testing of MVC controllers.

This commit introduces comparable methods in JsonPathRequestMatchers for client-side testing with a RestTemplate.

• isString()
• isBoolean()
• isNumber()
• isMap()