MATLAB Examples

Extend Model Coverage of a Test Case

Increase coverage of a test case by generating tests using Simulink® Design Verifier™. Copyright 2016 The MathWorks, Inc.


This example shows you how to extend coverage of a test case beyond an initial test case. You start by measuring coverage for the initial test which uses timeseries data. Then you can add new test cases to the Test Manager and simulate them and review aggregate coverage.

This example builds on the workflow from another Simulink® Test™ example, "Requirements-Based Testing for Model Development."

Paths and Example Files

Enter the following to store paths and filenames for the example and set the current folder.

filePath = fullfile(matlabroot,'toolbox','simulinktest','simulinktestdemos');
rollModel = 'RollAutopilotRevised';
testHarness = 'RollReference_LoggedDataTest';
testFile = 'RollRefTest.mldatx';

Background and Workflow for the Example

Tests commonly use timeseries inputs to exercise the model or a particular model component. Timeseries inputs can include logged data from simulation or from physical measurements. Logged data can cover important simulation cases, but not necessarily achieve full model coverage. If you have Simulink® Test™ and Simulink® Design Verifier™, you can generate test cases to increase test coverage and view cumulative coverage from a the new test cases.

This example uses an updated version of the Roll Reference subsystem, a test case, and a test harness for a timeseries input. The basic workflow is:

  1. Measure model coverage with the timeseries input
  2. Generate additional test cases for coverage not achieved in the first test case.
  3. Run the test cases and measure cumulative model coverage.

The Roll Reference subsystem is one component of an autopilot control system. The subsystem controls the reference angle of the aircraft's roll axis.

The Test Case and Timeseries Test Harness

The model contains a test harness RollReference_LoggedDataTest, which uses timeseries data from the base workspace. The test case collects MCDC coverage for the Roll Reference subsystem.

Run the Test and View Coverage Results

Set the current folder to a writable location. Open the test file RollRefTest:


In the Test Browser, expand the Logged Data and Coverage test suite. Highlight the RollReference Timeseries Input test case and click Run.

When simulation completes, in the Results and Artifacts pane, select the test case. In the test results, expand the Coverage Results section. The results show that the test achieves partial coverage for the Roll Reference subsystem:

  • Decision coverage: 80%
  • Condition coverage: 70%
  • MCDC 25%

Generate Tests to Increase Model Coverage

To generate additional tests for missing coverage data, right click the coverage result, and then select "Add Tests for Missing Coverage". This will open the dialog box shown below. In the "Test Case" dropdown, select "Create a new test case" option. Then click "OK".

This will launch Simulink® Design Verifier™ and create a new test case in the test browser:

Run the New Test Case

Highlight the "New Test Case 1" and click Run.

When simulation completes, in the Results and Artifacts section, select the result set and expand the Aggregated Coverage Results. The coverage results show the coverage result for the new test.

  • Decision: 100%
  • Condition: 100%
  • MCDC: 100%

clear filePath reqDoc rollModel testFile testHarness topModel;