rust armanriazi test mock

To create a test double or mock object in Rust, you can use the Mock struct provided by the mockers crate. First, add the mockers crate to your Cargo.toml file:

[dependencies]
mockers = "0.19.1"

Then, in your test code, you can create a mock object like this:

use mockers::mock;

// Define a trait that your original object implements
trait MyTrait {
    fn my_method(&self, arg: i32) -> i32;
}

// Create a mock object that implements the trait
let mock_object = mock!(MyTrait);

// Define expectations for method calls on the mock object
expect_method_call!(mock_object.my_method(42)).returning(|arg| arg * 2);

// Use the mock object in your tests
assert_eq!(mock_object.my_method(42), 84);

In this example, we define a trait MyTrait and create a mock object mock_object that implements this trait. We then set an expectation that when my_method is called with the argument 42, it should return 84. Finally, we can use the mock object in our tests by calling my_method on it and asserting that the return value is as expected.

By using the mockers crate, you can easily create mock objects and define expectations for method calls, allowing you to test your code in isolation.