Provide Java 10 compatibility

I ran the JUnit 5 build on jdk-10-ea and encountered a Mockito-related issue.

  JUnit Jupiter:TestFactoryTestDescriptorTests:streamsFromTestFactoriesShouldBeClosed()
    MethodSource [className = 'org.junit.jupiter.engine.descriptor.TestFactoryTestDescriptorTests', methodName = 'streamsFromTestFactoriesShouldBeClosed', methodParameterTypes = '']
    => org.mockito.exceptions.base.MockitoException: 

Mockito cannot mock this class: interface org.junit.jupiter.api.extension.ExtensionContext.

Mockito can only mock non-private & non-final classes.
If you're not sure why you're getting this error, please report to the mailing list.

Java               : 10
JVM vendor name    : Oracle Corporation
JVM vendor version : 10-ea+29
JVM name           : Java HotSpot(TM) 64-Bit Server VM
JVM version        : 10-ea+29
JVM info           : mixed mode
OS name            : Linux
OS version         : 4.11.6-041106-generic

Underlying exception : java.lang.UnsupportedOperationException: Cannot define class using reflection

See full log at: https://travis-ci.org/junit-team/junit5/builds/296747184 See JUnit 5 issue that tracks JDK-9+ related issues at: https://github.com/junit-team/junit5/issues/1063

I guess, there’s command line switch that transforms the exception into a warning.

[raphw]

This is fixed on master and will be part of the next Byte Buddy update.

[TimvdLippe]

Okay, that should be an easy fix: https://github.com/raphw/byte-buddy/blob/032d63eefca08d33b45e85e184dad28f752c6d76/byte-buddy-dep/src/main/java/net/bytebuddy/ClassFileVersion.java#L133 that depends on lines like https://github.com/raphw/byte-buddy/blob/032d63eefca08d33b45e85e184dad28f752c6d76/byte-buddy-dep/src/main/java/net/bytebuddy/ClassFileVersion.java#L72

E.g. if ASM defines an Opcode for Java 10, Byte Buddy can work on Java 10, such that Mockito works on Java 10, such that JUnit5 works on Java 10 😂