I would like to test the IPv6 stack on an embedded system. How can I do that? Would establishing a test link between this device and another PC be a "good enough" test?
I was thinking about using a tool like socat to establish the link.
Should I ask this here or on Stack Overflow?
Depends on the reason for performing the test. If you want to know whether the device can provide a certain function, you should test whether that function actually works. If the function is "can establish IPv6 TCP connections", then this is what you should test - connecting to a PC would then be good enough.
If you want to certify IPv6 support for the device, this test certainly wouldn't be sufficient. There are feature lists for IPv6 tests that are used in certification, e.g. the IPv6 Ready Logo.
The free, industry standard test suite you can use is the TAHI test sutie, which can be used to get an IPv6 Ready Logo for your device (mentioned by Martin in another answer).
The TAHI suite runs on FreeBSD and will test for basic functionality of your IPv6 stack. You will still need to test real-world use cases, like actually using the device over IPv6 rather than IPv4. ;-) (That is, having a working stack does not guarantee that your real-world use cases will work; someone may have erroneously opened an IPv4-only socket, or done something else in the code which is not IPv6-friendly.)
