5.1. Unit tests

In a software package as dynamic and collaborative as OpenFAST, confidence in multiple layers of code is best accomplished with a strong system of unit tests. Through robust testing practices, the entire OpenFAST community can understand the intention behind code blocks and debug or expand functionality quicker and with more confidence and stability.

Unit testing in OpenFAST modules is accomplished through test-drive. test-drive is compiled along with OpenFAST through CMake when the CMake variable BUILD_TESTING is turned on (default off) and the CMake variable BUILD_UNIT_TESTING is on (turned on by default when BUILD_TEST is on).

The BeamDyn and NWTC Library modules contain some sample unit tests and should serve as a reference for future development and testing.

5.1.1. Dependencies

The following packages are required for unit testing:

CMake
test-drive - Included in OpenFAST repo in unit_test/test-drive

5.1.2. Compiling

Compiling the unit tests is handled with CMake similar to compiling OpenFAST in general. After configuring CMake with BUILD_TESTING turned on, new build targets are created for each module included in the unit test framework named [module]_utest. Then, make the target to test:

cmake .. -DBUILD_TESTING=ON
make beamdyn_utest

This creates a unit test executable at openfast/build/unit_tests/beamdyn_utest.

5.1.3. Executing

To execute a module’s unit test, simply run the unit test binary. For example:

>>>$ ./openfast/build/unit_tests/beamdyn_utest
All tests PASSED

the pass or fail status is provided for each test as it’s run. An error message is output when the test fails. Failure cases display the following output:

>>>$ ./unit_tests/beamdyn_utest
# Testing: Crv
Starting test_BD_CheckRotMat ... (1/6)
    ... test_BD_CheckRotMat [PASSED]
Starting test_BD_ComputeIniNodalCrv ... (2/6)
    ... test_BD_ComputeIniNodalCrv [PASSED]
Starting test_BD_CrvCompose ... (3/6)
    ... test_BD_CrvCompose [PASSED]
Starting test_BD_CrvExtractCrv ... (4/6)
    ... test_BD_CrvExtractCrv [PASSED]
Starting test_BD_CrvMatrixH ... (5/6)
[Fatal] Uncaught error
Code: 1 Message: A(1,1) simple rotation with known parameters: Pi on xaxis:
Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO
ERROR STOP

Error termination. Backtrace:
#0  0xffff9f70d08b in ???
#1  0xffff9f70ddb3 in ???
#2  0xffff9f70f333 in ???

5.1.4. Adding unit tests

Unit tests should be included for each new, testable code block (subroutine or function). What is testable is the discretion of the developer, but an element of the pull request review process will be evaluating test coverage.

New unit tests can be added to a tests directory alongside the src directory included in each module. For example, a module directory may be structured as

openfast/
  └── modules/
      └── sampledyn/
          ├── src/
          │   ├── SampleDyn.f90
          │   └── SampleDyn_Subs.f90
          └── tests/
              ├── sampledyn_utest.F90
              ├── test_SampleDyn_Feature1.F90
              ├── test_SampleDyn_Feature2.F90
              └── test_SampleDyn_Feature3.F90

Each unit test file must contain a module that exports a function which populates a list of unit tests in accordance with the test-drive documentation. These modules contain subroutines which take an error argument that is populated by the check subroutine provided by test-drive. The sampledyn_utest.F90 collects all of the unit tests lists from the adjacent modules and runs them. These programs are compiled via the unit_tests/CMakeLists.txt file so all relevant modules and programs are specified there.

Refer to existing unit tests for the BeamDyn or NWTC Library unit tests for examples of how to structure and build the unit test drivers. Also review the test-drive documentation at test-drive.

Some useful topics to consider when developing and testing for OpenFAST are: