Before
```
expected Token::Str but serialized as Str(“F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4")
```
After
```
expected Token::Str(“f9168c5e-ceb2-4faa-b6bf-329bf39fa1e4”) but serialized as Str(“F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4")
```
The serde_test Serializer and Deserializer panic in is_human_readable unless the
readableness has been set explicitly through one of the hidden functions. This
is to force types that have distinct readable/compact representations to be
tested explicitly in one or the other, rather than with a plain assert_tokens
which arbitrarily picks one.
We need to follow up by designing a better API in serde_test to expose this
publicly. For now serde_test cannot be used to test types that rely on
is_human_readable. (The hidden functions are meant for our test suite only.)
This implements the KISS suggested in https://github.com/serde-rs/serde/issues/790.
It is possible that one of the other approaches may be better but this
seemed like the simplest one to reignite som discussion.
Personally I find the original suggestion of adding two traits perhaps slightly
cleaner in theory but I think it ends up more complicated in the end
since the added traits also need to be duplicated to to the `Seed`
traits.
Closes#790
Like what's been done on the deserialization side with MapVisitor, this
allows some weirder uses of Serde to handle the key and value in
separate steps.
David Tolnay