Testing the code¶
All additions and modifications to ASE should be tested.
Test scripts should be put in the ase/test directory. Run all tests with:
python -c "from ase.test import test; test(2)"
It is using the function:
When you fix a bug, add a test to the test suite checking that it is truly fixed. Bugs sometimes come back, do not give it a second chance!
How to fail successfully¶
Test scripts are run from within Python using the
Among other things, this provides the test scripts with an specialized global
namespace, which means they may fail or behave differently if you try
to run them directly e.g. using python testscript.py.
If a test script causes an exception to be thrown, or otherwise terminates in an unexpected way, it will show up in this summary. This is the most effective way of raising awareness about emerging conflicts and bugs during the development cycle of the latest revision.
Remember, great tests should serve a dual purpose:
- Working interface
- To ensure that the class’es and method’s in ASE are functional and provide the expected interface. Empirically speaking, code which is not covered by a test script tends to stop working over time.
- Replicable results
- Even if a calculation makes it to the end without crashing, you can never
be too sure that the numerical results are consistent. Don’t just assume
expressiondoes not evaluate to
from ase import molecule atoms = molecule('C60') atoms.center(vacuum=4.0) result = atoms.get_positions().mean(axis=0) expected = 0.5*atoms.get_cell().diagonal() tolerance = 1e-4 assert (abs(result - expected) < tolerance).all()
Using functions to repeat calculations with different parameters:
def test(parameter): # setup atoms here... atoms.set_something(parameter) # calculations here... assert everything_is_going_to_be_alright if __name__ in ['__main__', '__builtin__']: test(0.1) test(0.3) test(0.7)
Unlike normally, the module __name__ will be set to
when a test script is run by the test suite.