This is a maven specific problem I think. Maven does not copy the files form /src/main/resources
to the target-test folder. You will have to do this yourself by configuring the resources plugin, if you absolutely want to go this way.
An easier way is to instead put a test specific context definition in the /src/test/resources
directory and load via:
@ContextConfiguration(locations = { "classpath:mycontext.xml" })