Strong unit testing is the foundation of agile software development but embedded systems present special problems. Test of embedded software is bound up with test of hardware, crossing professional and organizational boundaries. Even with evolving hardware in the picture, agile methods work well provided you use multiple test strategies. This has powerful implications for improving the quality of highreliability systems, which commonly have embedded software at their heart. Keywords. Agile methodologies, Extreme Programming, Embedded Development, Embedded Agile, High Reliability Software, Real-time Software, Agile Testing.