Having searched Google for an answer, this looks like it might have something to do with Android development tools.
Below are steps taken from this comment thread:
- Right click on the project -> run -> run configuration
- Select your Junit project
- Go to the classpath tab
- remove the Android framework entry
- select bootstrap entries
- click on advanced
- select Add Library
- Ok
- Chose “JRE System Library”
- Next
- finish
- You need to also add the JUnit library so follow the steps 5 to 11 and select the “Junit” instead of “JRE System Library”
- You can now run your project as Junit.