PlcTestSuite

A user-friendly unit testing framework for TwinCAT 3 PLC programmers, designed to lower the barriers to Test-Driven Development.

Quick Start

1. Write Tests in Your MAIN Program

PROGRAM MAIN
VAR
    ReRun : BOOL;
END_VAR

TEST_Add();
TEST_Bool();

IF ReRun THEN
    TestSuite.ReRunTests();
    ReRun := FALSE;
END_IF

2. Add Test Methods

METHOD TEST_Add
VAR_INST
    Expected : DINT;
    Actual   : DINT;
END_VAR

IF TestSuite.Test(__POUNAME()).ExecuteTest() THEN
    Expected := 0;
    Actual   := -5 + 5;
    TestSuite.Test(__POUNAME()).AssertEqual(Expected, Actual);
END_IF

Key Points:

• Use VAR_INST for test variables (maintains state between cycles)
• Use __POUNAME() for automatic test ID generation
• Wrap logic in IF TestSuite.Test(__POUNAME()).ExecuteTest() THEN

3. Supported Types

AssertEqual() supports integers, booleans, strings, and floating-point (REAL/LREAL) with epsilon tolerance:

TestSuite.Test(__POUNAME()).AssertEqual(Expected, Actual, 0.1);  // epsilon = 0.1

Default epsilon: 0.000001

Configuration

Max Tests: Adjustable in library parameter settings (default: 50)

Output Path: C:\ProgramData\Beckhoff\TwinCAT\3.1\Boot\TEST_Result.xml (JUnit XML format)

Custom Suite Name: TestSuite.TestSuiteName := 'My Tests';

Version History

v1.1.2 - Added ADS logging functionality v1.1.1 - RPC enabled for ReRunTests() and ReRunIndividualTest() methods v1.1.0 - Result file generation (JUnit XML) v1.0.9 - Enhanced test infrastructure v1.0.8 - Added test suite naming for multiple instances v1.0.7 - Message improvements v1.0.6 - Code refactoring and naming consistency v1.0.5 - Naming adjustments v1.0.4 - Added ReRunIndividualTest() method v1.0.3 - Max tests exceeded handling, individual test suites v1.0.2 - REAL/LREAL epsilon comparison, Expected/Actual in failure messages v1.0.1 - Library packaging and releases folder v1.0.0 - Initial release with core test framework