Spring boot MVC framework allows developers to write Junit test cases to test REST API. the rest api calls are tested using Junit with the help of MockMVC class. One of the common error in rest json is “No value at JSON path”. In this article, let us discuss on this Assertion Error.
java.lang.AssertionError: No value at JSON path "$.name1"
at org.springframework.test.util.JsonPathExpectationsHelper.evaluateJsonPath(JsonPathExpectationsHelper.java:295)
at org.springframework.test.util.JsonPathExpectationsHelper.assertValue(JsonPathExpectationsHelper.java:98)
at org.springframework.test.web.servlet.result.JsonPathResultMatchers.lambda$value$2(JsonPathResultMatchers.java:111)
at org.springframework.test.web.servlet.MockMvc$1.andExpect(MockMvc.java:196)
at com.yawintutor.StudentTestController.testStudent(StudentTestController.java:38)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at org.junit.vintage.engine.execution.RunnerExecutor.execute(RunnerExecutor.java:40)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.Iterator.forEachRemaining(Iterator.java:116)
at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at org.junit.vintage.engine.VintageTestEngine.executeAllChildren(VintageTestEngine.java:80)
at org.junit.vintage.engine.VintageTestEngine.execute(VintageTestEngine.java:71)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:229)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:197)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:211)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:191)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:137)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.java:89)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: com.jayway.jsonpath.PathNotFoundException: No results for path: $['name1']
at com.jayway.jsonpath.internal.path.EvaluationContextImpl.getValue(EvaluationContextImpl.java:133)
at com.jayway.jsonpath.JsonPath.read(JsonPath.java:187)
at com.jayway.jsonpath.JsonPath.read(JsonPath.java:345)
at com.jayway.jsonpath.JsonPath.read(JsonPath.java:329)
at org.springframework.test.util.JsonPathExpectationsHelper.evaluateJsonPath(JsonPathExpectationsHelper.java:292)
... 56 more
Root Cause
The above exception occurs when a rest call is invoked and the mismatch of the rest call output and the expected value in the Junit test case. Rest call may not return json response or the expected value may not look for json.
How to reproduce this issue
If the key in the json response is different from the expected key in the Junit test case, then this issue may be reproduced. This issue will be reproduced in the following example.
package com.yawintutor;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTestController{
@Autowired
private WebApplicationContext webApplicationContext;
private MockMvc mockMvc;
@Before
public void setup() {
mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
}
@Test
public void testStudent() throws Exception {
mockMvc.perform(get("/student")).andExpect(status().isOk())
.andExpect(content().contentType("application/json"))
.andExpect(jsonPath("$.studentId").value("1"))
.andExpect(jsonPath("$.name1").value("student1"))
.andExpect(jsonPath("$.age").value(30));
}
}The response from JSON is as shown below.
{"studentId":"1","name":"student1","age":30}The JSON response is returned with key “name”, while the test case expects the key to be “$.name1”. The mismatch of the key causes this exception
Solution 1
Check the name of the key in the JSON response string and the expected key in the Junit test case. If both are different, modify the correct name of the key
package com.yawintutor;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTestController{
@Autowired
private WebApplicationContext webApplicationContext;
private MockMvc mockMvc;
@Before
public void setup() {
mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
}
@Test
public void testStudent() throws Exception {
mockMvc.perform(get("/student")).andExpect(status().isOk())
.andExpect(content().contentType("application/json"))
.andExpect(jsonPath("$.studentId").value("1"))
.andExpect(jsonPath("$.name").value("student1"))
.andExpect(jsonPath("$.age").value(30));
}
}Solution 2
In your Junit test case, add the code “.andDo(print())” and run the test case again, this will print the json response, check the name of the key and change it accordingly. The example below shows the JSON response string
package com.yawintutor;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTestController{
@Autowired
private WebApplicationContext webApplicationContext;
private MockMvc mockMvc;
@Before
public void setup() {
mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
}
@Test
public void testStudent() throws Exception {
mockMvc.perform(get("/student")).andExpect(status().isOk())
.andDo(print())
.andExpect(content().contentType("application/json"))
.andExpect(jsonPath("$.studentId").value("1"))
.andExpect(jsonPath("$.name1").value("student1"))
.andExpect(jsonPath("$.age").value(30));
}
}Solution 3
Check the path of the json key in the Junit test case, correct the path of the accessing key as shown in the below example.
{"studentId":"1","name":"student1","age":30, "address":{"street":"First Street","City":"Bangalore"}}Use the correct path in the Junit test case as shown below
.andExpect(jsonPath("$.address.street").value("First Street"))
instead of
.andExpect(jsonPath("$.street").value("First Street"))Solution 4
Junit converts the JSON response as array of the elements. Use the appropriate index to check the value in the test case. The example below shows how to assert the repeated value of the json in the test case.
@Test
public void testStudent() throws Exception {
mockMvc.perform(get("/student")).andExpect(status().isOk())
.andDo(print())
.andExpect(content().contentType("application/json"))
.andExpect(jsonPath("$[0].studentId").value("1"))
.andExpect(jsonPath("$[0].name").value("student1"))
.andExpect(jsonPath("$[0].age").value(30));
}Solution 5
The content of the response may not be returned as a json object. First, make sure it returns the json response as shown in the example below.
package com.yawintutor;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTestController{
@Autowired
private WebApplicationContext webApplicationContext;
private MockMvc mockMvc;
@Before
public void setup() {
mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
}
@Test
public void testStudent() throws Exception {
mockMvc.perform(get("/student").contentType(MediaType.APPLICATION_JSON))
.andExpect(status().isOk())
.andDo(print())
.andExpect(content().contentType("application/json"))
.andExpect(jsonPath("$.studentId").value("1"))
.andExpect(jsonPath("$.name1").value("student1"))
.andExpect(jsonPath("$.age").value(30));
}
}