clj-http-mock

A Clojure library for mocking clj-http requests.

This library is heavily influenced by clj-http-fake and borrows one or two functions from it. The main differences are:

Mock routes are defined in a vector, not a map, and are searched in order.
We use a different algorithm for matching routes, so avoid the combinatorial explosion of permutiations and cross-product.
The routes themselves are defined as maps, and allow for very flexible matching.

Installation

Available from Clojars:

[clj-http-mock "0.1.0"]

Usage

(require '[clj-http.client :as http]
         '[clj-http-mock.core :as mock])
         
(mock/with-mock-routes
  [(mock/route :get "http://www.google.com/")      
   (constantly {:status 200 :body "Mocked"})]
  (http/get "http://www.google.com/"))
;;=> {:status 200 :body "Mocked"}

To match any query parameters:

(mock/with-mock-routes
  [(mock/route :get "http;//www.google.com/" mock/any)
   (fn [{:keys [query-string]}]
     {:status 200 :body query-string})]
  (http/get "http://www.google.com?q=mock"))
;;=> {:status 200 :body "q=mock"}

Defining mock routes

Mock routes are defined as a vector. Requests are matched against the routes in the order they are defined, and the first match wins. If no mock route matches, the request is passed on to the original clj-http.core/request function unless *in-isolation* is true, in which case an exception is thrown. You can set in-isolation globally by calling (mock/set-in-isolation! true) or by using the helper macro mock/with-mock-routes-in-isolation to set up your mock routes.

A mock route is simply a Clojure map with the keys :method, :scheme, :host, :port, :path, and :query-params. The values in the map may be constants, regular expressons, sets, functions, maps, or nil, and are matched against the corresponding field in the request as follows:

nil matches (nil? val)
a function matches if (f val) returns a true value
a set matches if it contains val
a map matches if val is a map with the same keys and every value matches recursively according to these rules
a regular-expression matches if val is a matching string
anything else must match according to Clojure's =

(I'm open to supporting bag= for collections if that anyone needs that.)

There is special handling of :port to allow it to be unset in the mock route or the request if it is the default port for the scheme. There is also special handling of :path, which treats "" and / as equivalent.

For example, the following mock route:

  {:method :get 
   :scheme :http 
   :host "www.google.com"
   :port 80
   :path "/"
   :query-params {:q #".*"}}

would match all requests to http://www.google.com/?q=.*. The mock/route function exists to make it easier to define routes. Called with a single map argument, it will merge in some defaults, so the above is equivalent to:

(mock/route {:host "www.google.com" :query-params {:q #".*"}})

Called with an HTTP method (:get, :put, :post, etc.) and URL, it will parse the URL to generate the route map for you. So we could also write:

(mock/route :get "http://www.google.com/")

to match GET requests with no query string, or:

(mock/route :get "http://www.google.com/" {:q #".*})

which will produce the map we started with. If you don't need special matching of the query parameters (values are constants that much match literally), you can define your route like so:

(mock/route :get "http://www.google.com/?q=foo&sort=relevance")

Note that, because we parse the query string and match against the resulting map, this route will match both http://www.google.com/?q=foo&sort=relevance and http://www.google.com/?sort=relevance&q=foo.

The helper macros mock/with-mock-routes and mock/with-mock-routes-in-isolation expect their first argument to be a vector with an even number of elements (pairs of mock route and handler); subsequent expressions are evaluated with the appropriate bindings in place.

Generating responses

The clj-http-mock.response namespace contains a few functions for generating responses:

HTTP status 200, constant body

(ok-response "Body text")
HTTP status 200, body read from clojure.java.io/resource

(resource-response "my-mocks/page.html")
HTTP status 302, Location header set to url

(redirect-response url)
HTTP status 307, Location header set to url

(redirect-response url :status 307)
HTTP status 404, empty body

(not-found-response)

License