Unit Testing AutoCAD with NUnit + AcCoreConsole

This project demonstrates how to write and execute automated unit tests for AutoCAD drawings using:

• NUnit

• accoreconsole.exe — AutoCAD’s headless scripting engine

• AutoCAD .NET API

• AutoCAD 2026 (latest as of this writing — works for older and future releases too)

📦 NuGet Packages Used

This project uses the following NuGet packages:

Package	Version	Description
NUnit	4.3.2	Latest NUnit framework for writing test cases.
NUnitLite	4.3.2	Embedded lightweight runner to execute tests via AutoCAD Core Console.
ExtentReports	5.0.4	Beautiful HTML test report generator integrated with the tests.
AutoCAD.NET.Core	25.1.0	AutoCAD 2026 .NET API package for custom development and testing.

✅ Note: NUnitLite is used to self-host and run the tests from inside accoreconsole.exe, making the solution CI/CD friendly without needing an external test runner.

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🔧 Project Setup

1. Prerequisites

• AutoCAD 2026 installed

• .NET 8 SDK

• Visual Studio 2022+ with desktop development workload

• Access to required AutoCAD .NET reference assemblies (acdbmgd.dll, acmgd.dll etc.)

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2. Clone and Build

Before building, make sure AutoCAD assemblies are referenced correctly in the .csproj.

git clone https://github.com/MadhukarMoogala/coreconsolerunner.git
cd coreconsolerunner
msbuild /t:build coreconsolerunner.sln

✅ Running Tests

This project allows running NUnit-based unit tests against DWG files in three different ways:

✅ Summary of Logic Flow:

Case	Logic
1. Core Console	Use /i argument passed via command line
2. AutoCAD GUI, file open	Use active document path if available and saved
3. AutoCAD GUI, no doc or unsaved	Prompt user to select a .dwg file for testing

🟦 Case 1 – AutoCAD Core Console (accoreconsole.exe)

Best for CI pipelines and automation.

Steps:

1. Ensure your DWG test file path is passed using the /i switch.

2. Run the accoreconsole with a script file that NETLOADs your DLL and runs the RunCADtests command.

Example:

accoreconsole.exe /i "D:\Tests\testdrawing.dwg" /s "TestRun.scr"

TestRun.scr contents:

NETLOAD
D:\Path\To\Your\TestAssembly.dll
RunCADtests
QUIT
Y

🟦 Case 2 – AutoCAD GUI (Named Drawing)

Run tests on the currently opened DWG file in the AutoCAD GUI.

Steps:

1. Open your DWG file in AutoCAD.

2. Load your test DLL using NETLOAD.

3. Run the command:

Command: RunCADtests

🟦 Case 3 – AutoCAD GUI (Prompt User for File)

If no document is open, AutoCAD will prompt the user to select a .dwg file for testing.

Steps:

1. Start AutoCAD.

2. NETLOAD your DLL.

3. Run the command:

   1. Command: RunCADtests

4. A file dialog will appear asking for a DWG file.

5. After selection, tests will be run against that file in an off-screen side database.

📄 Sample Output

• Running in accoreconsole.exe with RunTests.bat

RunTests.bat
Current dir is now: D:\Work\repo\CoreConsoleTestRunner
Using accoreconsole at: D:\ACAD\watt\AutoCAD 2026\accoreconsole.exe
Running in AutoCAD mode...
Redirect stdout (file: C:\Users\moogalm\AppData\Local\Temp\accc315322).
AcCoreConsole: StdOutConsoleMode: processed-output: enabled,auto
AutoCAD Core Engine Console - Copyright 2025 Autodesk, Inc.  All rights reserved. (W.74.0.0)

Execution Path:
D:\ACAD\watt\AutoCAD 2026\accoreconsole.exe
Current Directory: D:\Work\repo\CoreConsoleTestRunner

Version Number: W.74.0.0 (UNICODE)
LogFilePath has been set to the working folder.
Regenerating model.
Drawing created using acadiso.dwt from AutoCAD profile: <<Unnamed Profile>>
**** System Variable Changed ****
1 of the monitored system variables has changed from the preferred value. Use SYSVARMONITOR command to view changes.


AutoCAD menu utilities loaded.
Command:
Command:

Command:
Command: SECURELOAD

Enter new value for SECURELOAD <0>: 0

Command: netload Assembly file name: "D:\Work\repo\CoreConsoleTestRunner\CoreConsoleRunner\bin\x64\Debug\net8.0-windows\win-x64\CoreConsoleRunner.dll"

Command: RunCADtests

Running NUnit tests...

Invalid or missing drawing path:
Command: QUIT
_Y
Really want to discard all changes to drawing? <N> _Y

Command:
QUIT

LogFilePath has been restored to ''.
Exit Code: 0

• Running from AutoCAD GUI

Test Reports

• XML results saved to:
  TestResult.xml

• Optional: Generate HTML reports using:

  • ExtentReports

    

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Project Structure

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Adding New Tests

To add a new AutoCAD entity test, create a class under the Tests/ folder using the same pattern as existing ones. Each test class must:

• Inherit from DrawingTestBase

• Be decorated with [TestFixture, Apartment(ApartmentState.STA), Category("EntityName")]

🆕 Example: LineTests

[TestFixture, Apartment(ApartmentState.STA), Category("Line")]
public class LineTests : DrawingTestBase
{
    private Line _line;

    public void GetFirstLine()
    {
        if (_line != null) return;

        var modelSpace = (BlockTableRecord)trans.GetObject(
            SymbolUtilityServices.GetBlockModelSpaceId(testDb),
            OpenMode.ForRead);

        foreach (ObjectId entId in modelSpace)
        {
            if (entId.ObjectClass.Name == "AcDbLine")
            {
                _line = trans.GetObject(entId, OpenMode.ForRead) as Line;
                break;
            }
        }

        if (_line == null)
            Assert.Fail("No line entity found in ModelSpace.");
    }

    [Test]
    public void LineLengthTest()
    {
        GetFirstLine();
        var test = TestReport.Extent.CreateTest(nameof(LineLengthTest));
        Assert.That(_line.Length, Is.EqualTo(100).Within(0.001));
        test.Pass($"Length: {_line.Length}");
    }

    [Test]
    public void LineStartPointTest()
    {
        GetFirstLine();
        var test = TestReport.Extent.CreateTest(nameof(LineStartPointTest));
        Assert.That(_line.StartPoint, Is.EqualTo(new Point3d(0, 0, 0)).Using<Point3d>((a, b) => a.IsEqualTo(b, new Tolerance(1e-6, 1e-6)) ? 0 : 1));
        test.Pass($"Start Point: {_line.StartPoint}");
    }
}

💡 Notes

• accoreconsole.exe is headless: ideal for CI/CD pipelines and regression testing.

• Ensure that SECURELOAD is set to 0 in script to allow .dll loading.

• Tests can inspect entities (e.g. Circle, BlockReference) using AutoCAD API.

🙏 Special Thanks

This project is inspired by:

• CADbloke/CADtest
  CADtest runs NUnitLite version 3 inside AutoCAD and/or the AutoCAD Core Console.

Highly recommended resource for plugin-level unit testing:

• AutoCAD/Civil 3D Plugin Unit Test with NUnit – Civil WHIZ
  A helpful guide on structuring NUnit-based tests in the context of AutoCAD and Civil 3D.](https://civilwhiz.com/docs/autocad-civil-3d-plugin-unit-test-with-nunit/)

✍️ Written By

Madhukar Moogala
Developer Advocate