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Back-to-Back (MIL/SIL) Equivalence Testing an Atomic Subsystem

This example shows how to create and run a back-to-back test, which is also known as an equivalence test, for an atomic subsystem.

Model with plant and controller subsystems

Generate Code for the Model

Open the model, configure the system on which you are running Simulink, and generate code for the whole model.

model = 'sltestMILSILEquivalence'; 
% Configure for code generation
if ismac
    lProdHWDeviceType = 'Intel->x86-64 (Mac OS X)';
elseif isunix
    lProdHWDeviceType = 'Intel->x86-64 (Linux 64)';
    lProdHWDeviceType = 'Intel->x86-64 (Windows64)';

set_param(model, 'ProdHWDeviceType', lProdHWDeviceType);
### Starting build procedure for: sltestMILSILEquivalence
### Successful completion of build procedure for: sltestMILSILEquivalence

Build Summary

Top model targets built:

Model                    Action                        Rebuild Reason                                    
sltestMILSILEquivalence  Code generated and compiled.  Code generation information file does not exist.  

1 of 1 models built (0 models already up to date)
Build duration: 0h 0m 56.894s

Create a Back-to-Back Test Using the Test Manager and Test For Model Component Wizard

1. Open the Test Manager.


2. Click New > Test For Model Component.

Menu selection for Test for Model Component

3. Click the Use current model icon icon.png to add the sltestMILSILEquivalence model to the Top Model field. Select Controller and click the plus sign. Then click Next.

Create test for model component wizard with controller subsystem selected

4. Select Use component input from the top model as test input. Then click Next.

Create test for model component wizard with using component input from the top model as test input selected

5. Select Perform back-to-back testing. Check that Simulation1 is set to Normal and Simulation2 is set to Software-in-the-Loop (SIL). Then click Next.

Create test for model component wizard with back-to-back testing selected

6. Leave the default values for saving the test data and generated test:

  • Select test harness input source: Inports,

  • Specify the file format: MAT

  • Specify location to save test data: sltest_sltestMILSILEquivalence

  • Test File Location: sltest_sltestMILSILEquivalence_tests

Then, click Done. The Create Tests for Model Component generates the back-to-back (equivalence) test and then returns to the Test Manager.

Create test for model component wizard with Inports as the test harness input source, MAT as the file format, and the default locations to save the test data and generated test.

7. In the Test Manager Test Browser pane, select the test file, sltest_sltestMILSILEquivalence_tests. Enable coverage collection by expanding the Coverage Settings section. Under Coverage to Collect, select Record coverage for system under test. Under Coverage Metrics, select Decision and MCDC. Coverage assesses the completeness of a test.

Coverage settings

8. Select the sltestMILSILEquivalence_Harness1 test case. Expand the Simulation 1 and Simulation 2 sections and their System Under Test and Simulation Settings and Release Overrides subsections to see the settings.

Test Manager with simulation one set for normal mode

Test Manager with simulation two set for software-in-the-loop mode

Run the Test and View the Results

1. Click Run in the Test Manager toolbar.

2. When the test run completes, in the Results and Artifacts pane, select Results and view the Aggregated Coverage Results section. Both the Normal and SIL simulations have 100% coverage, which indicates that testing is complete for the selected model coverage metrics.

Aggregated coverage results

3. Expand the Results hierarchy and select Out1:1 under Equivalence Criteria Result. The difference between the Normal and SIL simulations is zero, which shows that both simulations produce the same results.

Results display showing matching sim output for both simulations and zero difference between the signals

Close the Model and Clear and Close the Test Manager