Friday, May 24, 2013

Small features distinguishes Protest

Protest is a unit testing framework for C++ that make testing fun, fast, and simple (see introduction). Recently, after using it on one of my own project, I've added a few more features to it.

First, I improved the compilation time for compiling a .cc file containing a test cases. This was embarrassingly bad earlier, but now I think its pretty good. The issue was that there were a lot functions defined in the header. I did a bit of preprocessing magic to avoid unnecessary function definition (in favor of function declarations) and that lower the compilation times dramatically.

Second, I made the check macro a bit more intelligent. Protest's check macro was already quite smart: it's capable of dealing with matchers, and splitting the left hand side and the right hand side in a comparison (e.g., foo != bar), which means that there is no need for several check macros as is common for C++ unit test frameworks.
Anyway, while working on some bit twiddling heavy code my tests tended to look something like this:
    test("twiddling #2") {
        check(f(10) == 0x1f);
        check(f(11) == 0x2f);
and when a test failed the following was printed: f(10) == 0x1f (30 == 31) failed. [suite/twiddling #2][].
which is all pretty nice, isn't it? Well, not really.

I found myself having to convert the decimal print-outs to hexadecimal before the error made sense to me -- bit twiddling is not easy in base-10... It didn't take long until I wished that my favorite unit test framework did this automatically for me. How nice then that I had the author of it so conveniently close. Sitting on the very same chair even!

Fast forward one hour and Protest now gives the following print-out for the example above f(10) == 0x1f (0x1e == 0x1f) failed. [suite/twiddling #2][].
that is, Protest recognizes that I used hexadecimal literals in the check and changes the base of the integers in the print-out appropriately.

Pretty convenient.

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