The java.lang.Exception No runnable methods exception occurs when Junit detects no runnable test methods. In spring boot, the exception occurs where no test runnable methods are configured in junit test classes. The junit framework does not find a test method with the @Test annotation in the test class. The exception java.lang.Exception No runnable methods will therefore be thrown for invalid test class.
In the older version of the junit framework, the test method is identified with a method signature. The junit identifies the methods that begin with the word “test.” It runs all the methods starting with the word “test” in the test class to perform the unit test of the source code.
In the recent version of the junit framework, the test method is identified by an annotation @Test. The junit identifies all the methods that have the @Test annotation in the test class, performs a unit test of the source code.
The error java.lang.Exception No runnable methods is thrown when a Junit test case is run in the spring boot test environment. This exception and the solution for this exception will be discussed in this article.
Exception
The exception stack trace log will be shown as below for the junit vintage error java.lang.Exception No runnable methods
java.lang.Exception: No runnable methods
at org.junit.runners.BlockJUnit4ClassRunner.validateInstanceMethods(BlockJUnit4ClassRunner.java:191)
at org.junit.runners.BlockJUnit4ClassRunner.collectInitializationErrors(BlockJUnit4ClassRunner.java:128)
at org.junit.runners.ParentRunner.validate(ParentRunner.java:416)
at org.junit.runners.ParentRunner.<init>(ParentRunner.java:84)
at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.<init>(SpringJUnit4ClassRunner.java:137)
at org.springframework.test.context.junit4.SpringRunner.<init>(SpringRunner.java:49)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder$DefensiveAnnotatedBuilder.buildRunner(DefensiveAllDefaultPossibilitiesBuilder.java:113)
at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder.runnerForClass(DefensiveAllDefaultPossibilitiesBuilder.java:56)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.vintage.engine.discovery.ClassSelectorResolver.resolveTestClass(ClassSelectorResolver.java:66)
at org.junit.vintage.engine.discovery.ClassSelectorResolver.resolve(ClassSelectorResolver.java:47)
at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.lambda$resolve$2(EngineDiscoveryRequestResolution.java:129)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1351)
at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126)
at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:498)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:485)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
at java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:152)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:464)
at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:174)
at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolve(EngineDiscoveryRequestResolution.java:120)
at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.resolveCompletely(EngineDiscoveryRequestResolution.java:87)
at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolution.run(EngineDiscoveryRequestResolution.java:80)
at org.junit.platform.engine.support.discovery.EngineDiscoveryRequestResolver.resolve(EngineDiscoveryRequestResolver.java:112)
at org.junit.vintage.engine.discovery.VintageDiscoverer.discover(VintageDiscoverer.java:42)
at org.junit.vintage.engine.VintageTestEngine.discover(VintageTestEngine.java:62)
at org.junit.platform.launcher.core.DefaultLauncher.discoverEngineRoot(DefaultLauncher.java:177)
at org.junit.platform.launcher.core.DefaultLauncher.discoverRoot(DefaultLauncher.java:164)
at org.junit.platform.launcher.core.DefaultLauncher.discover(DefaultLauncher.java:120)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.<init>(JUnit5TestReference.java:45)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.createUnfilteredTest(JUnit5TestLoader.java:76)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.createTest(JUnit5TestLoader.java:66)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.loadTests(JUnit5TestLoader.java:53)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:525)
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)
Root Cause
The junit framework searches the @Test annotation method in the test class. In the spring boot test environment, the test class should have at least one test method with @Test annotation. If none of the methods have a @Test annotation, this exception java.lang.Exception No runnable methods will be thrown.
This exception will be resolved by making one of the methods as a test method by adding a @Test annotation.
How to reproduce this issue
In the spring boot application, in the test environment, create a test class with test methods that do not have a @Test annotation. The junit framework searches methods with a @Test annotation. Since the test class does not contain a method with a @Test annotation, this error “java.lang.Exception: No runnable methods” will be thrown.
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.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();
}
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 1
In the spring boot test environment, in the test class, add at least one test method and add @Test annotation to the test methods. This will solve this exception in the spring boot test class. The following code resolves the “java.lang.Exception: No runnable methods” error.
package com.test;
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 some cases, the @Test annotation will be loaded from different packages. Verify the name of the @Test annotation package. If you are using a Test class from a different package, this exception may happen.
use
import org.junit.Test;
instead of
import org.junit.jupiter.api.Test;