Spring annotation based configuration not found with SpringJUnit4ClassRunner - spring

Question

I have some JUnit (4.10) tests configure using Spring (3.1.3) like this:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes=TestConfig.class)
public class MyTest {...}
These run fine from within Eclipse, but with Maven (surefire) from the command-line it fails to find the TestConfig class. I used to have the same configuration using xml based configuration and that worked fine in both cases. I have verified that TestConfig.class is in the expected location in test-classes. I also tried to move it to classes in case the context loader didn't look in test-classes, but no luck. Any ideas?
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:157)
...
Caused by: java.io.FileNotFoundException: class path resource [com/test/TestConfig.class] cannot be opened because it does not exist
at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:157)
at org.springframework.core.type.classreading.SimpleMetadataReader.<init>(SimpleMetadataReader.java:49)
at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:80)
at org.springframework.core.type.classreading.CachingMetadataReaderFactory.getMetadataReader(CachingMetadataReaderFactory.java:101)
at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:76)
at org.springframework.context.annotation.ConfigurationClassParser.findAllAnnotationAttributes(ConfigurationClassParser.java:282)
at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:225)
at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:148)
at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:134)
Update
I had <forkMode>never</forkMode> for the maven-surefire-plugin.
Setting <forkMode>once</forkMode> (default) made the problem go away.