Debugging and testing your code

Ensuring that your code is correct can be very difficult, so IMP provides a number of tools to help you out.

The first set are assert-style macros to use in the C++ code:

• IMP_USAGE_CHECK() which should be used to check that arguments to functions and methods satisfy the preconditions.
• IMP_INTERNAL_CHECK() which should be used to verify internal state and return values to make sure they satisfy pre and post-conditions.

See the checks page for more details. As a general guideline, any improper usage should produce at least a warning and all return values should be checked by such code.

The second is logging macros such as:

• IMP_LOG() which allows controlled display of messages about what the code is doing. See logging for more information.

Finally, each module has a set of unit tests. The tests are located in the modules/modulename/test directory. These tests should try, as much as possible, to provide independent verification of the correctness of the code. Any file in that directory or a subdirectory whose name matches test_*.{py,cpp}, medium_test_*.{py,cpp} or expensive_test_*.{py,cpp} is considered a test. Normal tests should run in at most a few seconds on a typical machine, medium tests in 10 seconds or so and expensive tests in a couple of minutes.

Python tests can, in principle, be any Python script that exits without error if the test passes. However, in most cases it makes sense to use the Python unittest framework. We provide a custom test case subclass that provides some useful IMP-specific functions (IMP::test::TestCase). The convention in IMP is for tests to make a subclass of this class called Tests (this makes it easier to run individual tests from the command line). Some tests will require input files or temporary files. Input files should be placed in a directory called input in the test directory. The test script should then call

self.get_input_file_name(file_name) 

to get the true path to the file. Likewise, appropriate names for temporary files should be found by calling

self.get_tmp_file_name(file_name) 

.