improve propertyHelper for failure messages

[leobalter]

Example:
Before: descriptor value should be 42 Expected SameValue(«1», «0») to be true
After: descriptor value should be 42

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Note that Expected SameValue(«1», «0») is for the list of failures while checking the descriptor, as each error adds up to the list. The error message is confusing if the expected value is similar, e.g. 1:

descriptor value should be 42 Expected SameValue(«1», «0») to be true

[ljharb]

This doesn’t seem like an improvement; showing the actual value alongside the expected value seems pretty critical.

[leobalter]

@ljharb this is exactly the problem, the assertion was using internal actual and expected values, not anything from the user input.

This assertion was only telling if it found any failures while checking the descriptor.

Note that we already use the same assertion message - through failures.join('; ') - to inform of a different value or other failures.

[ljharb]

Thanks, i get it now :-)