Saturday, February 14, 2015

Rapid Cycle Testing with C++

I discovered the convenience of rapid cycle testing in Clojure with "midje" and liked it.  I then re-created it while learning some Ruby.  Now I'm refreshing my C++ skills and wanted the same thing, and decided to combine it with GoogleTest (gtest) and clang on my Mac.

As usual when combining tools, it took a bit of fiddling to get it all playing nicely.  In hopes of saving somebody else some time, I uploaded a sample project to GitHub.


NOTE: has dependencies on other tools; see for details.

I'll probably change my workflow a lot over time, but that minimal example seems to work pretty well.  Run ./ in one window and an editor in another.  Every time you write a source file, the automated test runs.  For example:

$ ./ 

Now I write "learn.cpp" out, and the autotest window spits out:

autotest: /Users/sford_itunes/drop_sford/Dropbox/sford/src/c++11/autotest-cpp/learn.cpp

[ 33%] Built target gtest
[ 66%] Built target gtest_main
Scanning dependencies of target runUnitTests
[100%] Building CXX object CMakeFiles/runUnitTests.dir/learn.cpp.o
Linking CXX executable runUnitTests
[100%] Built target runUnitTests
        1.77 real         1.40 user         0.19 sys

Running main() from
[==========] Running 2 tests from 2 test cases.
[----------] Global test environment set-up.
[----------] 1 test from CoutTests
[ RUN      ] CoutTests.Simple
Hello world
[       OK ] CoutTests.Simple (0 ms)
[----------] 1 test from CoutTests (0 ms total)

[----------] 1 test from VarInits
[ RUN      ] VarInits.Simple
[       OK ] VarInits.Simple (0 ms)
[----------] 1 test from VarInits (0 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 2 test cases ran. (1 ms total)
[  PASSED  ] 2 tests.
        0.00 real         0.00 user         0.00 sys
tst Sun Feb 15 14:28:25 CET 2015

        1.79 real         1.40 user         0.20 sys

It's a little verbose; I'll probably tighten it up a bit.  Note that it takes almost 2 seconds, most of which is in the build step.  That's on a second generation Macbook Air.  I miss the sub-second cycle time of Clojure Midje and Ruby autotest, but oh well.

By the way, if you download the project from GitHub, you will note that there is no CMakeLists.txt file, and you'll wonder how it can be using cmake.  Just follow the readme instructions and run the ./ script.  That script creates the CMakeLists.txt file.  (It seemed like a good idea at the time...)

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