How to Mock and Unit Test SharePoint Online Custom Code Without Commercial Tools Like Typemock

Mocking and unit testing SharePoint Online custom code can be a complex task due to the dependencies on SharePoint’s APIs and environment. However, you can achieve this without relying on commercial tools like Typemock. This guide will walk you through the process of creating a mock environment using open-source tools and best practices.

1. Implement Dependency Injection

One of the fundamental steps in making your code testable is to implement Dependency Injection (DI). This allows you to inject mock objects into your classes, making it easier to isolate and test them.

Define Interfaces: Start by defining an interface for the SharePoint service. Implement Interfaces: Create a concrete implementation of the interface. Inject Dependencies: Use DI to inject the interface into your custom code. public interface ISharePointService { Liststring GetListItems(string listName); } class SharePointService : ISharePointService { public Liststring GetListItems(string listName) { // Code to get items from SharePoint list } } class MyCustomCode { private readonly ISharePointService _sharePointService; public MyCustomCode(ISharePointService sharePointService) { _sharePointService sharePointService; } public void ProcessItems() { var items _(YourListName); // Process items } }

2. Create Mock Objects

Mock objects can be created manually or using a mocking library like Moq or NSubstitute. Here’s how to create a simple mock manually:

public class MockSharePointService : ISharePointService { public Liststring GetListItems(string listName) { return new Liststring { // Mock data }; } }

3. Write Unit Tests

Use a testing framework like NUnit or MSTest to write your unit tests. Here’s an example using NUnit:

using ; [TestFixture] public class MyCustomCodeTests { [Test] public void ProcessItems_ShouldProcessItems() { // Arrange var mockService new MockSharePointService(); var customCode new MyCustomCode(mockService); // Act (); // Assert // Check the expected outcome } }

4. Use In-Memory Data Structures

If your custom code interacts with data structures, consider using in-memory collections or objects to simulate SharePoint data. This can simplify testing and make it easier to set up different scenarios.

Liststring listData new Liststring { Item1, Item2, Item3 };

5. Avoid Direct Calls to SharePoint APIs

Whenever possible, abstract calls to SharePoint APIs behind interfaces as shown in the DI example. This allows you to replace these calls with mock objects in your tests.

6. Integration Testing

For scenarios that require testing the actual interaction with SharePoint, consider writing integration tests that run in a controlled environment. This may involve using a dedicated SharePoint Online tenant.

Summary

By following these steps, you can effectively mock and unit test your SharePoint Online custom code without relying on commercial tools. The key is to leverage Dependency Injection, create mock implementations, and use open-source testing frameworks. This approach will help you maintain the testability of your code while ensuring that it behaves correctly.