https://github.com/arichiardi/unbroken-promises
Tiny macro library designed for easing up ClojureScript testing of Promises.
https://github.com/arichiardi/unbroken-promises
clojure clojurescript promises
Last synced: 29 days ago
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Tiny macro library designed for easing up ClojureScript testing of Promises.
- Host: GitHub
- URL: https://github.com/arichiardi/unbroken-promises
- Owner: arichiardi
- License: unlicense
- Created: 2019-02-04T03:29:24.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-02-06T00:13:06.000Z (over 6 years ago)
- Last Synced: 2025-04-28T15:17:54.279Z (29 days ago)
- Topics: clojure, clojurescript, promises
- Language: Clojure
- Homepage:
- Size: 40 KB
- Stars: 15
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# ClojureScript UnBroken Promises
This is a library designed for easing up ClojureScript async testing of
Promises.
[](https://clojars.org/unbroken-promises)
```clojure
[unbroken-promises "0.1.9"]
```
```clojure
unbroken-promises {:mvn/version "0.1.9"}
```
### Readability and robustness
Two macros have been designed for helping with the perilous task of
[testing async code in ClojureScript](https://clojurescript.org/tools/testing#async-testing):
`is-resolved` and `is-rejected`.
Testing `js/Promise` resolution at the moment reads:
```clojure
(deftest the-fetch-test
(cljs.test/async done
(-> (fetch "http:/foo.com/bar.json")
(.then (fn [result]
(is (some? result))
(is (= result "bar"))))
(.then done))))
```
But thanks to `unbroken-promises.macro` it becomes:
```clojure
(ns my-namespace-under-test
(:require [unbroken-promises :as ubp :include-macros true]))
(deftest the-fetch-test
(ubp/is-resolved [result (fetch "http:/foo.com/bar.json")]
(is (some? result))
(is (= result "bar"))))
```
Not only the former is arguably cleaner but it also correctly handles the case
when the promise unexpectedly rejects, reporting it as testing error.
Analogously, `unbroken-promises/is-rejected` makes sure we correctly test
rejections:
```clojure
(deftest the-rejection-test
(ubp/is-rejected [err (js/Promise.reject (js/Error. "Oh Noes!"))]
(is (= "Oh Noes!" (.-message err)))))
```
Same convenience feature as above, in case of resolution we want a test error.
### Nitty gritty details
The last thing to be aware of is that this library is also responsible of
writing the messages that you see in the test report.
The `context` entries, in `clojure.test` parlance, are computed by
`unbroken-promises.data/file-and-line-before-promise`. Some (very naive)
heuristic tries to return the right file line/column coordinates. Please report
any issue you encounter so that I can tweak things.
---
> NOTE: You cannot have more than one async test per deftest form or only the first one will run.
Because of the above ClojureScript restriction **only one macro per `deftest`
is allowed**.
You should never have more than one `is-resolved`/`is-rejected` in a `deftest`
because **only the first macro** will be evaluated **silently ignoring the
others**.
---
## Unlicensed Software
See [The Unlicense](http://unlicense.org/).