### Install via Open UPM

Source: https://github.com/mackysoft/unity-serializereferenceextensions/blob/main/README.md

Install the package using the OpenUPM CLI by running the provided command in your terminal.

```bash
openupm add com.mackysoft.serializereference-extensions
```

--------------------------------

### Install via Git URL

Source: https://github.com/mackysoft/unity-serializereferenceextensions/blob/main/README.md

Install the package by adding the git URL to Unity's Package Manager. To pin a specific version, append the version number after a '#'.

```bash
https://github.com/mackysoft/Unity-SerializeReferenceExtensions.git?path=Assets/MackySoft/MackySoft.SerializeReferenceExtensions#1.7.0
```

--------------------------------

### Basic Usage of SubclassSelector

Source: https://github.com/mackysoft/unity-serializereferenceextensions/blob/main/README.md

Apply the [SerializeReference] and [SubclassSelector] attributes to an interface field to enable a dropdown for selecting concrete implementations. Supports collections and provides execution logic in Start.

```csharp
using System;
using UnityEngine;

public class Example : MonoBehaviour {

	// The type that implements ICommand will be displayed in the popup.
	[SerializeReference, SubclassSelector]
	ICommand m_Command;

	// Collection support
	[SerializeReference, SubclassSelector]
	ICommand[] m_Commands = Array.Empty<ICommand>();

	void Start () {
		m_Command?.Execute();

		foreach (ICommand command in m_Commands) {
			command?.Execute();
		}
	}

	// Nested type support
	[Serializable]
	public class NestedCommand : ICommand {
		public void Execute () {
			Debug.Log("Execute NestedCommand");
		}
	}

}

public interface ICommand {
	void Execute ();
}

[Serializable]
public class DebugCommand : ICommand {

	[SerializeField]
	string m_Message;

	public void Execute () {
		Debug.Log(m_Message);
	}
}

[Serializable]
public class InstantiateCommand : ICommand {

	[SerializeField]
	GameObject m_Prefab;

	public void Execute () {
		UnityEngine.Object.Instantiate(m_Prefab,Vector3.zero,Quaternion.identity);
	}
}

// Menu override support
[AddTypeMenu("Example/Add Type Menu Command")]
[Serializable]
public class AddTypeMenuCommand : ICommand {
	public void Execute () {
		Debug.Log("Execute AddTypeMenuCommand");
	}
}

[Serializable]
public struct StructCommand : ICommand {
	public void Execute () {
		Debug.Log("Execute StructCommand");
	}
}
```

--------------------------------

### Run EditMode Tests Locally

Source: https://github.com/mackysoft/unity-serializereferenceextensions/blob/main/AGENTS.md

Execute EditMode tests for the project using Unity's batchmode. Ensure UNITY_EXE is set to your Unity executable path. This command generates an XML report of the test results.

```bash
PROJECT_ROOT="$(pwd)"
RESULT_XML="$PROJECT_ROOT/TestResults/editmode.xml"

mkdir -p "$(dirname "$RESULT_XML")"

"<UNITY_EXE>" -batchmode -nographics -quit \
  -projectPath "$PROJECT_ROOT" \
  -runTests -testPlatform editmode \
  -testResults "$RESULT_XML"
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.