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Test harness for SlimKernel

Overview

The goal of this package is to make writing high-level tests exciting by building sufficient architecture around them, that would make it easy and expressive to build your test cases.

Installation

Core concepts

SlimKernelHttpClient

This class acts as a HttpClient directing the requests at the provided Slim App, which is at it’s core a Request Handler. The most basic usage is to use one of the convenience methods modeled after HTTP verbs:

• $httpClient->get("/url")
• $httpClient->head("/url")
• $httpClient->post("/url", payload: [...])
• $httpClient->put("/url", payload: [...])
• $httpClient->patch("/url", payload: [...])
• $httpClient->delete("/url")

Or a more advanced, by crafting the request manually (or using the provided RequestBuilder) and passing it to the request() method.

Each request is by default expected to succeed, as determined by returning a HTTP status code in the 1xx-3xx range. You can change the behaviour by calling the withResponseExpectation method:

• withResponseExpectation(ResponseExpectation::Failure) — codes greater or equal to 4xx
• withResponseExpectation(ResponseExpectation::Success) — below 4xx, the default
• withResponseExpectation(ResponseExpectation::None) — status code assertions disabled

Hint: when building test cases outside the happy path, such as making sure your authorization mechanism works correctly, you will want to use the ResponseExpectation::Failure mode.

HttpResponseAssertion

Each SlimKernelHttpClient returns a HttpResponseAssertion, which helps you make common assertions about the response and access its contents. Example helper methods:

• assertSuccess() and assertFailure() (useful you called with the ResponseExpectation::None)
• expectJson() asserts the response was a valid JSON and return its parsed data
• isSuccessful() indicates if the response http code is in the 1xx-3xx range
• assertRedirect($to = null) asserts the response is a redirect and optionally makes sure the Location header matches the provided value
• slimErrorPage() returns an object representing the default Slim error page, so you can make assertions about the thrown exception type or its message

The PSR-7 Response object is available as a public $response field. For convenience, the calling SlimKernelHttpClient is also attached as $httpClient.

Use Cases (KernelHttpUseCase trait)

To organize your test cases, and make reusable actions, it’s good to organize your sources into use cases. These use cases are an SDK of sorts for your app. They represent an abstraction over your application’s API. Look at the examples:

The trait is here to provide a couple of convenience methods. Since most of your use cases will only use the SlimKernelHttpClient as the entrypoint into your app, this is the only dependency for your use cases. The trait provides the factory method of($httpClient) to create an instance, the constructor to store the client in a protected field, and two helper methods to control the response expectation: expectFailure() and noResponseExpectation()

Assertions (JsonListResponseAssertion and others)

To build a robust test suite, most of your API endpoints will need a custom assertion class (responsible for holding the response data and making assertions on it). One particularly interesting instance of this are assertions about endpoints listing multiple records. Their handling can be made easier by using the JsonListResponseAssertion:

It automatically provides the ofJsonResponse factory method, which can directly take the result of a $httpClient->request() call. An advanced usage of the assertions and use cases is presented in the examples folder.

Middlewares

Inputs for a high-level e2e test are such complex and diverse. Different clients craft different payloads, which include:

• JSON payloads
• multipart/form-data or application/x-www-form-urlencoded payloads
• Requests with basic auth, bearer tokens or client certificates
• Stateful session cookies or other similar authentication mechanisms

It’s challenging to fit all this complexity and provide keep the simple interface such as the SlimKernelHttpClient has. The package solves this problem by allowing adding a PSR-15 middlewares to the client. Two basic ones are built in:

• $httpClient->json() adds an Accept header to indicate json payloads are expected, as well as the X-Requested-With header to simulate a browser
• $httpClient->withBaseUrl($url) will prefix each request url with a given value
• use $httpClient->withMiddleware() to add a custom one

Custom middlewares in combination with different use cases for different clients of your app can be very powerful. You can look at the (example middlewares)[examples/middlewares] to a glimpse of how they can be used.