Are there any software libraries and/or wireless drivers that make it possible to turn a sequence of binary data into a wireless packet in the air? For example, if someone used Airpcap / Wireshark to capture a series of interesting packets, is there some library that can be fed that binary data in order to turn it back into 802.11 wireless packets for testing purposes? If so, can we then also make minor alterations to the values of the packet in order to generate a wide variety of testing scenarios? Is anyone aware of tools/libraries that enable or assist this scenario?
Most Wi-fi tools are set up for cracking networks or stealing data so you might be able to re-purpose an existing attacker's tool or library (like ettercap or aircrack-ng) for your testing purposes. Most tools I've encountered focus on ethernet, tcp and http.
The following list of software might merit further investigation:
Bit-Twist and TCPReplay are your best bet if you're willing to compromise for something higher up in the protocol stack.