| Abstrakt: |
The purpose of this study was to identify fault-prone functions that are likely to contain faults in a given software system. Five metrics were used: Di, an internal design metric which incorporates factors related to a function's internal structure; De, an external design metric which focuses on a function's external relationships to the rest of the software system; D(G), a composite design metric which is a linear combination of Di and De; and the union and intersection of Di, De, and D(G). Since the system being considered was already developed, a very important aspect of our study was to extract the design information directly from the source code rather than from the corresponding design documentation which may not exist or, if it does exist, it may be incomplete, difficult to understand, or not updated. To make the analysis more accurate and efficient, a metric analysis tool (χMetrics) was implemented. We conducted experiments using χMetrics on part of a distributed software system, written in C, with a clientserver architecture, and identified a small percentage of its functions as good candidates for fault-proneness. Files containing these functions were then validated by the real defect data collected between a recent major release and its subsequent release for their fault-proneness. The results indicate that our metrics are good indicators of fault-prone functions. Two extra experiments were also conducted to show that function size cannot replace any of our metrics; and where the function size was factored out our metrics performed better than the normalized metrics. The important benefit of our metrics is that they help project managers determine where additional testing effort should be spent and possibly which fault-prone functions should be assigned to more experienced programmers if modifications are required. Copyright © 2000 John Wiley & Sons, Ltd. |
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