Unit Testing AutoCAD with NUnit + AcCoreConsole

By Madhukar Moogala

Why Unit Test AutoCAD Code?

If you’re developing on the AutoCAD .NET API (AcDb managed layer)—handling things like blocks, entities, transactions, dynamic properties, or geometry—you probably want:

• Inspires confidence that your logic works across DWG files
• Repeatable tests that run in isolation
• Fast feedback without relying on GUI interaction

That’s exactly what this project enables.

This is not for UI-level testing (dialogs, palettes, CUI). It’s for AcDb-level logic.

What This Project Enables

This project shows how to:

• Run unit tests on DWG files via accoreconsole.exe
• Use NUnit/NUnitLite to test AutoCAD logic like circles, lines, blocks, and more
• Generate HTML reports with ExtentReports
• Run tests in:
  • AutoCAD GUI (on active or selected DWG)
  • AcCoreConsole (headless)
  • Side databases (for isolated testing)

How It Works

Tests inherit from a base class DrawingTestBase, which handles:

• Opening a DWG (via command-line args or prompt)
• Creating transactions
• Managing AutoCAD Database instances
• Detecting whether running inside accoreconsole.exe or full GUI

You trigger tests using the RunCADtests command, either:

In AcCoreConsole:

accoreconsole.exe /i sample.dwg /s TestRun.scr

In AutoCAD GUI:

NETLOAD your test DLL
Command: RunCADtests
→ Optionally select a drawing if one isn't open
→ Tests run and output an HTML report

Sample Test

Here’s a basic test for verifying a circle’s radius:

[TestFixture, Apartment(ApartmentState.STA)]
public class CircleTests : DrawingTestBase
{
[Test]
public void CircleRadiusTest()
{
var circle = GetFirstCircle();
Assert.That(circle.Radius, Is.EqualTo(50));
}
}

You can write similar tests for:

• Blocks (dynamic/static)
• Line geometry
• Property evaluation
• Transaction behavior

Project Structure

• /Tests: Place test classes here (CircleTests.cs, LineTests.cs, etc.)
• /TestInfrastructure: Contains base classes and utilities
• /TestRun.scr: AutoCAD script to load and invoke tests
• RunTest.bat: Launches accoreconsole with a selected DWG and script

Getting Started

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

Modify the script/batch to point to your DWG and test assembly. Run using accoreconsole or AutoCAD
GUI.

Inspired By

Special thanks to:

• CADbloke/CADtest
• AutoCAD/Civil
  3D plugin unit test with NUnit – Civil WHIZ

Footnote

This approach makes it easier to bring modern testing practices to AutoCAD plugin development—
especially AcDb logic. If you’re building custom entities, automations, or design validations, give
this a try.