Explain clojure.test assertion failures without dependencies
"Unleash the power of copy-and-paste"
You need to install bbin:
brew install babashka/brew/bbin
and
echo 'export PATH="$PATH:$HOME/.babashka/bbin/bin"' >> ~/.$(basename $SHELL)rc && exec $SHELL
With that out of the way, you can now use bbin to install elucidate:
bbin install io.github.pesterhazy/elucidate
One step at a time. By default, the output of clojure.test assertions can be hard to read:
user=> (is (= {:foo 1 :bar 2} {:foo -1 :bar 2}))
FAIL in () (NO_SOURCE_FILE:1)
expected: (= {:foo 1, :bar 2} {:foo -1, :bar 2})
actual: (not (= {:foo 1, :bar 2} {:foo -1, :bar 2}))
So let's copy what comes after actual: to the clipboard. The clipboard should now contain this string:
(not (= {:foo 1, :bar 2} {:foo -1, :bar 2}))
Now you can pipe the result into elucidate:
pbpaste | elucidate
The output should look like this:
{:bar 2, :foo -1 +-1}
You can also copy the entire assertion failure output:
FAIL in () (NO_SOURCE_FILE:1)
expected: (= {:foo 1, :bar 2} {:foo -1, :bar 2})
actual: (not (= {:foo 1, :bar 2} {:foo -1, :bar 2}))
and elucidate will find the "actual" part automatically.
clojure.test/is prints failures in a concise, readable way. But when checking equality of maps, it's sometimes hard to spot differences. Tools like and humane-test-output change the test runner to pretty-print failures. While this works great, it has a few disadvantages:
- Pretty-printing output doesn't always make the result more readable
- Extra dependencies are needed
- Complexity is added
elucidate takes the opposite approach. When a test fails, you copy-and-paste the failure output into a separate program. This gives you an optional way to make the output more digestible without adding complexity to the test runner. It works with Clojure/ClojureScript/babashka.
The following assertions are supported:
(is (= v1 v2))(is (submap? v1 v2))(submap?)
All the actual work is done by deep-diff2.