Over a million developers have joined DZone.

Clojure: Use expect-let To Share A Value Between expected And actual

· Java Zone

Learn more about how the Java language, tools and frameworks have been the foundation of countless enterprise systems, brought to you in partnership with Salesforce.

 Most of the time you can easily divorce the values needed in an expected form and an actual form of an expectation. In those cases, nothing needs to be shared and your test can use a simple bare expect. However, there are times when you need the same value in both the expected and actual forms - and a bare expect doesn't easily provide with a way to accomplish that.

In version 1.4.16 or higher of expectations, you can now use the expect-let macro to let one or more values and reference them in both the expected and actual forms.

Below is a simple example that makes use of expect-let to compare two maps that both have a DateTime.

(ns blog-expectations
  (:use expectations)
  (:import [org.joda.time DateTime]))

(defn timestamp-event [m t]
  (assoc m :time t))

(expect-let [now (DateTime.)]
            {:time now}
            (timestamp-event {} now))

If possible you should prefer expect, but expect-let gives you another option for the rare cases where you absolutely need to share a value.


Discover how the Force.com Web Services Connector (WSC) is a code-generation tool and runtime library for use with Force.com Web services, brought to you in partnership with Salesforce.

Topics:

Published at DZone with permission of Jay Fields, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}