Integration Testing MongoDB Realm Serverless Functions

Today we’ll focus on the middle layer of the testing pyramid: integration tests.

Integration tests are designed to test the integration of two or more components that work together as part of the application. A component could be a piece of the code base. A component could also exist outside of the code base. For example, an integration test could check that a function correctly saves information in a database. An integration test could also test that a function is correctly interacting with an external API.

When following the traditional test pyramid, a developer will write significantly more unit tests than integration tests. When testing a serverless app, developers tend to write nearly as many (or sometimes more!) integration tests as unit tests. Why?

Serverless apps rely on integrations. Serverless functions tend to be small pieces of code that interact with other services. Testing these interactions is vital to ensure the application is functioning as expected.

Example Integration Test

Let’s take a look at how I tested the integration between the storeCsvInDb Realm Serverless Function, the removeBreakingCharacters Realm Serverless Function, and the MongoDB database hosted on Atlas. (I discuss what these functions do and how they interact with each other and the database in my previous post.)

#mongodb #integration #serverless