Learn how to write R code with fewer bugs.

The problem with programming is that you are always one typo away from writing something silly. Likewise with data analysis, a small mistake in your model can lead to a big mistake in your results. Combining the two disciplines means that it is all too easy for a missed minus sign to generate a false prediction that you don t spot until it s too late. Testing is the only way to be sure that your code, and your results, are correct.

Testing R Code teaches you how to perform development-time testing using the testthat...