kubernetes-mock-rs

Mock Kubernetes client for testing things that interact with the Kubernetes API, including controllers.

View documentation, examples, and more on docs.rs and crates.io!

488 lines of code, but that's 24% doc comments.

Features

• Very simple to mock, just make the same API calls as your program should make
• Easy setup errors with good documentation - if there are problems, it should help you solve them
• Verbose errors when tests fail, showing you exactly what went wrong
• Works with multiple versions of Kubernetes (currently v1.25, v1.21) - to change versions, please use features v1_25 or v1_21.
  • Default is v1.25, if you want to use a different version please remember to use default-features = false in your Cargo.toml

Example

Minimal compilable example:

use kubernetes_mock::*;
use kube::{Api, api::ListParams};
use k8s_openapi::api::core::v1::Node;
#[tokio::main]
async fn main() {
    let (client, mut mocker) = make_mocker();
    let api: Api<Node> = Api::all(client);
    mocker.expect(|| async {
        let nodes = api.list(&ListParams::default()).await;
      },
      MockReturn::List(&[Node::default()]),
    ).await.unwrap();
    // ...
    let handle = tokio::spawn(mocker.run());
    api.list(&ListParams::default()).await;
    handle.await.unwrap().unwrap(); // Assert tests pass with `unwrap()`.
    // Requires two calls to unwrap - one for tokio spawn result, the other for the mocker result
}

Note: unwrap() is not great for formatting, if you'd like to see errors pretty printed you can do the following:

if let Err(e) = handle.await.unwrap() { // still need one unwrap() for tokio spawn
    panic!("{e:#?}"); // debug pretty-print
}

Still Todo

• Testing mocker.watch() - it works but is not tested.
  • We could use a controller to test this, to show how it works.
• More edge cases tested - functions passed to expect() panicking, etc.
• Explore better API design?
  • Can we let expect() take multiple API calls, meaning people can use one for all API calls
• Should/could we be less restrictive (e.g. unordered API calls, allowing the same call multiple times/"more than once", allowing different parameters)?

Feel free to help, check out CONTRIBUTING.md!

Distributed under Apache 2.0. See LICENSE for more information.