Crate mocha

A lightweight, simple and efficient HTTP mock server that can be used for local tests as well as tests that span multiple systems. It provides a local (or remote) mock server and a library to create, verify and remove HTTP mocks.

Usage

If used without a dedicated (standalone) mock server instance, an HTTP mock server will automatically be created in the background of your tests. The local mock server is created in a separate thread that will be started when a test needs a mock server for the first time. It will be shut down at the end of the test run.

Should you need to extend or change your tests to span multiple systems later (such as in system integration tests), you can switch the tests to use a standalone mock server by simply setting the address of the remote server using an environment variable. This way the remote server will be used for mocking and your mocks will be available to all participating systems. A standalone version of the HTTP mock server is available as an executable binary or a Docker image.

Getting Started

You can use a local mock server in your tests like shown in the following:

extern crate mocha;

use mocha::mock;
use mocha::Method::GET;

#[test]
fn simple_test() {
   // Arrange the test by creating a mock
   let health_mock = mock(GET, "/health")
      .return_status(200)
      .return_header("Content-Type", "application/text")
      .return_header("X-Version", "0.0.1")
      .return_body("OK")
      .create();

   // Act (simulates your code)
   let response = reqwest::get("http://localhost:5000/health").unwrap();

   // Make some assertions
   assert_eq!(response.status(), 200);
   assert_eq!(health_mock.number_of_calls(), 1);
}

As shown in the code snippet, a mock server is automatically created when the mock function is called. You can provide expected request attributes (such as headers, body content, etc.) and values that will be returned by the mock to the calling application using the [expect_xxx] and [return_xxx] methods, respectively. The [create] method will eventually make a request to the mock server (either local or remote) to create the mock at the server.

You can use the mock object returned by the [create] method to fetch information about the mock from the mock server, such as the number of times this mock has been called. This object is useful for test assertions.

A request is only considered to match a mock if the request contains all attributes required by the mock. If a request does not match any mock previously created, the mock server will respond with an empty response body and a status code 404 (Not Found).

Structs

HttpMockConfig
Mock

Enums

Method

Functions

mock
start_server