The quality of onboard flight software plays a significant role in the effort to succeed with more demanding space mission requirements. To improve software quality, the Japan Aerospace Exploration Agency (JAXA) has applied software independent verification and validation (IV&V) for various software systems. As part of this activities, test analysis has been conducted on some dependable flight software. The aim is to establish a methodology to efficiently identify "what to test", and also to obtain the points of view in test design that is adequate to each spacecrafts characteristics. For this purpose, we have introduced the concept of viewpoint of testing, enacted test analysis based on the concept, and evaluated existing test suites using these results. In this paper, we describe the concept and methodology of test analysis for dependable flight software based-on our experiences, as well as the result of our evaluations of existing test suites.