MATLAB Examples

Testing a Library and a Linked Block

Verify a reusable subsystem in a library and in a larger system. Copyright 2016 The MathWorks, Inc.


This example demonstrates a test case that confirms a library block meets a short set of requirements. After testing the library block, you execute a baseline test of a linked block and capture the baseline results. You then promote the baseline test harness to the library.

The library block controls a simple heatpump system by supplying on/off signals to a fan and compressor, and specifying the heatpump mode (heating or cooling).

Open the Test File

Enter the following to store paths and filenames for the example, and to open the test file. The test file contains a test case for the library block and for the block instance in a closed-loop model.

filePath = fullfile(matlabroot,'toolbox','simulinktest','simulinktestdemos');
testFile = 'sltestHeatpumpLibraryTests.mldatx';
library = 'sltestHeatpumpLibraryExample';
system = 'sltestHeatpumpLibraryLinkExample';

Expand the Library Block Test test suite, and highlight the Requirements Scenarios test case in the test browser. Expand the Test Harness section of System Under Test, and click the arrow to open the test harness for the library block.

open_system(library);[library '/Controller'],'Requirements_Tests');

The Test Sequence block sets three scenarios for the controller:

  • The controller at idle
  • The controller activating the fan only
  • The controller activating the heating anc cooling system

The Test Assessment block in the test harness checks the signals for each scenario. Since the test inputs and assessments are contained in the test harness, and no baseline data is being captured, the test case is a simulation test.

Run the Requirements-Based Test

In the test manager, run the Requirements Scenarios test case. The verify statement results show that the control_out signals pass.

Open the Linked Block Model

In the test manager, expand Instance Test. Highlight the Baseline Test test case. In the System Under Test, click the arrow next to the Model field to open the model.

sltest.harness.close([library '/Controller'], 'Requirements_Tests');

The controller is a linked block to the library. It is associated with a test harness Baseline Test that compares simulation results of the instance against baseline data. In your workflow, successful baseline testing for an instances of a library block can show that the linked block simulates correctly in the containing model. The test harness supplies a sine wave temperature and captures the controller output.

Run the Baseline Test and Observe Results

In the test manager, click Run to execute the test. The results show that the baseline test passes.

Move the Test Harness to the Library

If you develop a particularly useful test for a linked block, you can promote the test harness from a linked block to the source library block. The test harness then copies to all future instances of the library block.

Move the Baseline_controller_tests test harness to the library block:

1. In the sltestHeatpumpLibraryLinkExample model, click the harness badge and hover over the Baseline_controller_tests test harness.

2. Click the harness operations icon

3. Select Move to Library. A dialog informs you that the operation deletes the test harness from the instance and adds it to the library. Click Yes.

4. The test harness moves to the Controller library block.