hyperfiddle 2022-03-23 | Slack Archive

How to expect an exception cleanly with RCF?

(defn 💣 [] (/ 1 0))

(rcf/tests
 (ex-message (clojure.test/is (thrown? ArithmeticException (💣))))
 := "Divide by zero")

Done this way, my expectation leaks on both sides of :=.

👀 1

Daniel Jomphe13:03:21

#Also sent to the channel

Some experiments. But still, parts of the expectation appears on LHS.

(catch-a :message (💣)) := "Divide by zero"

(ns test
  (:require [clojure.test :as test]
            [hyperfiddle.rcf :refer [tests]]))

(defn 💣 [] (/ 1 0))

(defmacro catch-a [k & body]
  `(try ~@body
        (ex-info "Expected something thrown!" {}) ; don't throw it!
        (catch Exception e#
          (~k (first (:via (Throwable->map e#)))))))

(tests

 (+ 1 2) := 3

 (ex-message (test/is (thrown? ArithmeticException (💣))))
 := "Divide by zero"

 ;;(catch-a :message 1) := 1

 (catch-a :message (💣)) := (catch-a :message (💣))
 (catch-a :message (💣)) := "Divide by zero"

 (catch-a :type (💣)) := (catch-a :type (💣))
;;(catch-a :type (💣)) := java.lang.ArithmeticException  ; <>!?

 ;;
 )

Geoffrey Gaillard16:03:43

#Also sent to the channel

The current version of RCF doesn’t provide a way to expect exceptions. We are working on a version where we could leverage clojure.test/assert-expr. It already defines thrown? so we’ll get exception handling for free. Here is the feature request: https://github.com/hyperfiddle/rcf/issues/47

Dustin Getz17:03:41

The next version of RCF has much better facilities for adding features like this, no public release ETA but we are using it internally

Daniel Jomphe17:03:23

Thanks to both of you. In the meantime we don't mind doing the kind of things above. We're slowly ramping up on RCF usage. 🙂

🙂 2

Daniel Jomphe13:03:21

replied to a thread:How to expect an exception cleanly with RCF? (defn 💣 [] (/ 1 0)) (rcf/tests (ex-message (clojure.test/is (thrown? ArithmeticException (💣)))) := "Divide by zero") Done this way, my expectation leaks on both sides of `:=`.

Some experiments. But still, parts of the expectation appears on LHS.

(catch-a :message (💣)) := "Divide by zero"

(ns test
  (:require [clojure.test :as test]
            [hyperfiddle.rcf :refer [tests]]))

(defn 💣 [] (/ 1 0))

(defmacro catch-a [k & body]
  `(try ~@body
        (ex-info "Expected something thrown!" {}) ; don't throw it!
        (catch Exception e#
          (~k (first (:via (Throwable->map e#)))))))

(tests

 (+ 1 2) := 3

 (ex-message (test/is (thrown? ArithmeticException (💣))))
 := "Divide by zero"

 ;;(catch-a :message 1) := 1

 (catch-a :message (💣)) := (catch-a :message (💣))
 (catch-a :message (💣)) := "Divide by zero"

 (catch-a :type (💣)) := (catch-a :type (💣))
;;(catch-a :type (💣)) := java.lang.ArithmeticException  ; <>!?

 ;;
 )

Geoffrey Gaillard16:03:43

replied to a thread:How to expect an exception cleanly with RCF? (defn 💣 [] (/ 1 0)) (rcf/tests (ex-message (clojure.test/is (thrown? ArithmeticException (💣)))) := "Divide by zero") Done this way, my expectation leaks on both sides of `:=`.

The current version of RCF doesn’t provide a way to expect exceptions. We are working on a version where we could leverage clojure.test/assert-expr. It already defines thrown? so we’ll get exception handling for free. Here is the feature request: https://github.com/hyperfiddle/rcf/issues/47

2022-03-23

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