转载：Cost Benefits Analysis of Test Automation

Conclusion

Test automation is not always necessary, appropriate, or cost effective. In cases where we are making decisions based upon an expected return on investment, analysis can direct us to where test automation can benefit us. These returns are best computed by comparing
the costs and gains achieved through test automation over manual testing. Good management decisions can made about using automation to improve testing by identifying and estimating test automation costs
and benefits. This also helps to identify which factors we need to focus on to make the most of our investments.

When automation is required, either by contract or due to technical constraints, ROI computation may not be helpful. Intangible factors may constitute the bulk of the return, and thus arithmetic computations
won’t indicate the real value of automation. Fortunately in these situations we often aren’t faced with questions about the value of automation because it must be employed regardless.

When we want to understand the value of test automation there are several computational approaches we might employ. Some currently published equations have serious drawbacks and management decisions made based
on their use may be flawed. To avoid mistakes, misplaced expectations, and disappointment with automation we need to carefully assess the relevant factors applicable to each test situation, determine if there is cost or gain associated with automation, and
estimate the amount of it. These factors should be compared between automated and manual testing of the same areas or we should aggregate costs and benefits across sets of manual and automated tests. Alternate forms of equations can be used to provide similar
results based on the same ROI computation approaches.