Tests are an essential part of the development process. Their aim is to check that the different portions of the code meet their design and behave as intended. Providing an exhaustive guide about how to write tests in python is beyond the scope of this document, so in this section we will instead explain the details of the tests in turbomoleio: how they are organized, what are the tools available and how you should proceed to introduce tests for your new developments.

In turbomoleio we divide the tests in two groups. The definition could be considered somewhat arbitrary with respect to the standard ones, but in the following we use the following naming convention:

  • unit tests: aiming at testing each single component on its own (no TURBOMOLE executable runs inside these tests).

  • integration tests: testing the integration among different components and in particular with the TURBOMOLE executables.

When implementing a new feature you should always implement a series of tests before adding it to turbomoleio. It is also important to consider adding new tests when a bug is identified and fixed. This will prevent that such a bug will be reintroduced in later developments.

The test suite

The testing suite is based on pytest and makes wide use of its functionalities, like for example fixtures, marking and custom command line arguments. The pytest package should thus be installed and the tests should be executed using the pytest command. For a reference on all its features you can refer to the pytest documentation. To get the coverage of the tests you also need to install the pytest-cov package.

Summing up, aside from the standard dependencies in turbomoleio, the easiest way to prepare your environment to run the tests is to run

pip install pytest pytest-cov mongomock

To run the integration tests of course a standard installation of Turbomole should be available, so that the tests can call the different executables.

Once this is done you can run each test separately going to the different folders and executing the pytest command or use the runtest.sh script present in the root folder of the project. Running runtest.sh -u will run all the unit tests, while runtest.sh -i will run all the integration tests. In both cases it will produce a detailed report of the level of coverage. If you wish, you can then run

coverage html -d coverage_html

to generate an html version of the coverage report. The configurations for the coverage are given in the .coveragerc_unit and .coveragerc_integration files, present in the root folder of the project.

Unit tests

As mentioned above, we call unit tests those that test each single component on its own. Each module folder in turbomoleio contains a tests subfolder where the unit tests for all the components in that module are implemented. All the functions, objects and their methods have some unit test that will verify that it behaves as expected. This is done, for example, by checking:

  • the returned values of functions and methods,

  • the attributes set in objects,

  • the side effects of a function (e.g. creation or modification of files),

  • that the expected exceptions are raised under specific conditions,

These tests will be limited to a specific component and thus may require to mock functions or objects to determine a specific outcome of the test (see this guide for some examples). Mocks are also required for all the calls towards external applications and in particular to the TURBOMOLE executables. Since in the turbomoleio code the calls to TURBOMOLE executables is done for the DefineRunner class, specific mocks will be done for its testing.

For all the cases where inputs and outputs should be read or modified a set of prepared files are used. These files, mainly Turbomole inputs and outputs, are stored in the turbomoleio/testfiles folder. Using these test files and with the additional help of the mocking it is possible to direct and verify in detail what happens inside the component under test. For this reason the unit tests can achieve a very high coverage rate, of the code, where by coverage we intend the fraction of the lines of code that are executed by at least one test. As of version 1.0.0 the global coverage of the unit tests alone is 99% and developers should aim at keeping this value as high as possible.

The unit-testing for the output files is performed for multiple versions of Turbomole. The reference files for these tests are stored in the turbomoleio/testfiles/outputs folder for each Turbomole version, e.g. turbomoleio/testfiles/outputs/TM_v7.3.1. Additionnally, a turbomoleio/testfiles/outputs/generation folder contains the necessary information to generate new output files for a new Turbomole version using a specific development script (see Unit-tests for output parsing).

Integration tests

Integration tests aim to verify the integration between the different components and in particular with the Turbomole executables. For this reason they are all collected in the turbomoleio/integrations_tests folder and, to allow to execute them separately, they are all marked by setting the integration pytest mark for each module:

pytestmark = pytest.mark.integration

Since, aside from in DefineRunner, in the turbomole source code there are no explicit calls to TURBOMOLE executable, the integration tests will also check if the I/O features implemented keep working in the same way when the files are directly used or produced by TURBOMOLE. To be more explicit one can check if a file that has been produced or modified with turbomoleio keeps being read correctly in TURBOMOLE and if an output file produced by an execution of TURBOMOLE is still parsed correctly. For some functionalities anyway there is not really a meaning in performing an integration test. In these cases the portion of the code can be excluded from the coverage analysis.

The integration tests are all performed using the turbomoleio.testfiles.utils.run_itest() helper function. This first runs define using DefineRunner based on the parameters given in input, the produced control file is compared with a reference stored previously. If successful the required turbomole executables are run and the outputs are extracted using the objects implemented here. The numerical values of these outputs are checked with a respect to references stored in JSON files. Note that the comparison is performed using the turbomoleio.testfiles.utils.assert_almost_equal(). For this comparison some values are outright excluded from the check. In some cases a comparison will be obviously meaningless (e.g. the date of execution, the elapsed time), while in some other cases the values, while physically and chemically equivalent, may be reported in slightly different ways in the TURBOMOLE output and it would be extremely impractical to make a meaningful comparison for them (e.g. the order of the acoustic modes from aoforce can vary on different machines, even for the same version of TURBOMOLE. While checking the list of eigenvalues is trivial, verifying that the two lists of eigenvectors, represented in different order, are indeed equivalent up to a numerical tolerance would be cumbersome).

This procedure is repeated for different kinds of inputs and for the different TURBOMOLE executables currently supported by the turbomoleio objects.

Aside from preventing the introduction of errors when modifying existing parts of the code, integration tests can thus be used to verify that the implemented I/O functionalities will keep working for new versions of TURBOMOLE. It is inevitable that when moving from one TURBOMOLE version to another at least some of the integration tests will fail. This might be for some changes in the inputs, in the underlying implementations or even for some options being removed or renamed altogether. Another possibility is that the output given in the stdout has changed its format and that the parser now fails to correctly extract the results of the calculation. turbomoleio has been initially developed to target TURBOMOLE version 7.3 and the tests are designed for that specific version only. As new versions of TURBOMOLE are released the tests can be updated to match the new input and outputs definitions, but care should be taken by checking exactly which part of the test is leading to a failure.

In light of all this, two custom options have been added to pytest in turbomoleio. The first is a way to tune the value of the tolerance when comparing numerical values. This can be changed by running the tests with the --itest-tol. For example running

pytest --itest-tol=0.01

performs a much looser comparison (note that this is an absolute tolearance). The second option is --generate-itest-ref. When running the tests with this option, instead of using the reference files to check the correctness of the outputs produced by the tests, the outputs will instead be used to generate a new version of the JSON reference files and overwrite the previous ones.


The --generate-itest-ref should be used with extreme care. The original files provided with turbomoleio have been tested across different machines to verify that the tests pass on different environments. This option should be used only if the output objects parser are changed or if the reference version of TURBOMOLE is updated. In any case it would be wise not to run the whole set of tests with this option, but instead target only the specific test for which the reference file should be updated. For example:

pytest --generate-itest-ref test_dscf.py -k test_run_dscf_hf

Writing integration tests that trigger all the possible cases in the code is basically impossible. Some errors and checks in the source code are only triggered in presence of exceptional errors (e.g. wrongly formatted output files) and this cannot be easily reproduced systematically. In addition, while there is no strict limit for the execution time of a single test, these should be short enough to be executed in a reasonable amount of time with small computational resources. Lastly for some functions and objects there is little gain in testing their behavior in direct connection with an actual TURBOMOLE calculation. For all these reasons the aim for the coverage of the integration tests is lower compared to the unit tests. As of version 1.0.0 the integration tests alone cover 89% of the turbomoleio source code.

Writing new tests

New contributions to turbomoleio should always come with their set of unit and, if suitable, integration tests. The tests that you add should be organized in the same way as the other tests already available, as described in the previous sections.

The test functions and files should be named starting with test_ to be correctly discovered by pytest (this can be customized, but sticking to the standard is the easiest option). If you have some experience with the standard python testing utils, notice that in turbomoleio you should not subclass unittest.TestCase, since this is incompatible with some of the functionalities in pytest. All the options provided by TestCase can be easily replaced by pytest options and fixtures.

As for the other developments, you can use the tests already present as a reference for implementing your own. Several resources are available online discussing the testing best practices and the pytest documentation is a good starting point as well. Here we will limit to the description of the options and utils specific to turbomoleio.

Helper functions and utilities specific for testing can be found in the turbomoleio.testfiles.utils module. In particular this contains a context manager that is used in most of the tests present in the test suite: turbomoleio.testfiles.utils.temp_dir(). Whenever you write a test that needs to access files from or write files to the file system this should be done in a temporary directory specific for the test, otherwise the files will be written all over the project folders. This context manager can be easily used to create the temporary directory, optionally change directory to that one, and changing back to the initial directory when leaving the context manager, optionally deleting the temporary directory..

This function can be used in connection with the delete_tmp_dir fixture, that should be passed to its delete argument. The delete_tmp_dir, a boolean value True by default, can be switched to False calling pytest with the --keep-tmpdir option. When this happens the path to the temporary folder will be printed (with the print function) by temp_dir. This means that you will have this in the output for the failing tests and this will give you the way to inspect the files that were used and produced by the test and better understand why a test has failed.

delete_tmp_dir, as well as the other general fixtures, is implemented in the pytest standard conftest.py file in the root folder of the project, with the others being mainly options to ease the access to the test files. These files are stored in the turbomoleio/testfiles folder. You can add there the files that might be needed for your unit and integration tests. Modifying existing files is possible, even though discouraged. If it cannot be avoided (e.g. for the update to a new TURBOMOLE version) you should at least check that all the tests relying on the files that you plan to modify will keep working as expected.

Tests for output parsing

In order to create a new unit test for output parsing, you should:

  1. Create a test directory in the ~turbomoleio/testfiles/outputs/generation directory.

The test directory should be in the executable directory (i.e. the directory with the same name as the Turbomole executable being tested). The executable directory should be created if it is not yet there. The name of the test directory itself should be descriptive of the test. For example, if you create a test for an ridft output, using benzene and a specific exchange correlation functional, you could create a directory ~turbomoleio/testfiles/outputs/generation/ridft/benzene_myxc. This test-specific generation folder is referenced hereafter as the TESTGEN folder. The executable under testing is referenced hereafter as TESTEXEC and the name of the test is referenced hereafter as TESTNAME. An excerpt of the directory tree structure of the entire generation folder is shown hereafter:

    ├── aoforce
    │   ├── aceton_full
    │   └── h2_numforce
    └── dscf
        ├── aceton_dftd3_tzvp
        ├── h2o_std
        ├── h2o_uhf
        ├── nh3_cosmo_fermi
        └── nh3_dftd1
  1. Add the test in the tests_config.yaml in the ~turbomoleio/testfiles/outputs/generation folder.

  2. Place the coord file of the molecule/system in the TESTGEN folder.

  3. Create a test.yaml file in the TESTGEN folder.

This test.yaml file should contain the relevant information to automatically generate the control file and run the Turbomole executable or possibly a series of Turbomole executables (in case the tested executable cannot be run without a prior calculation). Look at other test.yaml files to see how this file is structured.

  1. Generate the reference files using the generate_output_files.py development script:

    python generate_output_files.py –test TESTEXEC TESTNAME –generate_control

6. Add the test in the tests_config.yaml current Turbomole version directory of ~turbomoleio/testfiles/outputs/TM_vX.Y.Z. For example, if this new test is added in turbomoleio 1.5, corresponding to Turbomole v7.7.1, add the test in the file ~turbomoleio/testfiles/outputs/TM_v7.7.1/tests_config.yaml.

Turbomole version change

When the version of Turbomole changes, two main things have to be performed.

  1. Check integration tests and regenerate reference files.

  2. Check and generate test output files for the new version (unit-tests for parsing).

The actions to be performed when changing from one Turbomole version to the next one is listed below. More details are also provided after the standard procedure.

Standard procedure

The following assumes you change from one version of Turbomole to the next one. For example, turbomoleio 1.5.x is fully compatible with Turbomole version 7.7. To change to Turbomole version 7.7 (and thus turbomoleio 1.5.x), change your Turbomole distribution to version 7.7 and apply the following list of actions.

  1. Integration tests

    1.1 Run pytest -m “integration”

    1.2 If there are errors (very likely) in 1.1, run pytest -m “integration” –dryrun-itest to generate a json file containing the differences between the two versions (both at the level of the control file and at the level of the generated output files). Very often, the main differences are due to different values or options generated by define for the control file. You can also run the new version of Turbomole with the old control file using pytest -m “integration” –dryrun-itest –dryrun-use-reference-control. Check carefully whether these differences are critical. Take appropriate measures if the differences are critical.

    1.3 If no critical differences are found, generate the new reference control and output files using pytest -m “integration” –generate-itest-ref.

  2. Output parsing

    2.1 Go in ~turbomoleio/dev_scripts and run python generate_output_files.py –dryrun. A parsing_update_differences.json file is created in the new test version directory with the list of differences for each output parsing test with respect to the previous Turbomole version. By default, the old control file is used for this dry run.

    2.2 Inspect the differences found in 2.1. If the differences are reasonable, generate the new reference files for the new Turbomole version by running python generate_output_files.py –generate_control. By default, the directory for the new Turbomole version is “TM_vX.Y.Z”.

    2.3 Update the list of supported Turbomole versions for the output parsing in ~turbomoleio/testfiles/utils.py by appending “TM_vX.Y.Z” to the list.

3. Change the minor version of turbomoleio for the new Turbomole version as described in Versioning.

Integration tests

For the integration tests, the check and generation is performed using the pytest infrastructure. The integration tests are run using:

pytest -m “integration”

This will run the integration tests with the version of Turbomole found in the system. Most likely, a series of errors will occur. A “dryrun” execution of the integration tests can then be performed to analyze the differences with respect to the previous Turbomole version using:

pytest -m “integration” –dryrun-itest

In that case, a json file containing the differences with respect to the previous Turbomole version will be generated. This json file (by default “dryrun_itest.json”) contains the differences found in the control file as well as in the output files for each integration test. You can change the path and name of this json file with the –dryrun-fpath option of pytest.

Most of the time, the main difference arises from different default values generated by define in the control file. It can be useful to compare the newest Turbomole version with the older one using the previous reference control file using:

pytest -m “integration” –dryrun-itest –dryrun-use-reference-control

If the differences found using this setup are small, one should in principle safely assume that transition can be performed. The reference files for the integration tests are then regenerated using:

pytest -m “integration” –generate-itest-ref

Note that this will override all the previous reference files and should be performed with care (first checking the differences as described above) !

Unit-tests for output parsing

In order to keep backward compatibility of the parsing of the outputs of previous Turbomole versions, output files and reference serialized objects for the new Turbomole version have to be checked and generated. Note that the old output files and reference serialized file objects are kept and still tested. A development script has been implemented to facilitate the generation of the new output files and reference serialized file objects. This script is located in:


Run the script using “–help” to get a list of the options available for this script.

It is important to know that the script can be run either in dry mode or in generation mode. In dry mode, a parsing_update_differences.json file is generated with all the differences found in the tests between the current Turbomole version and the control and output files of the previous Turbomole version.