Great efforts are currently underway to develop industrial applications for artificial intelligence (AI), especially those using machine learning (ML) techniques. Despite the intensive support for building ML applications, there are still challenges when it comes to evaluating, assuring, and improving the quality or dependability. The difficulty stems from the unique nature of ML: namely, that the system behavior is derived from training data, not from logical design by human engineers. This leads to black-box and intrinsically imperfect implementations that invalidate many of the existing principles and techniques in traditional software engineering. In light of this situation, the Japanese industry has jointly worked on a set of guidelines for the quality assurance of AI systems (in the QA4AI consortium) from the viewpoint of traditional quality-assurance engineers and test engineers. We report the initial version of these guidelines, which cover a list of the quality evaluation aspects, a catalogue of current state-of-the-art techniques, and domain-specific discussions in four representative domains. The guidelines provide significant insights for engineers in terms of methodologies and designs for tests driven by application-specific requirements.