Function assert_de_tokens_error

pub fn assert_de_tokens_error<'de, T>(tokens: &'de [Token], error: &str)
where
    T: Deserialize<'de>,

Asserts that the given tokens yield error when deserializing.

#[derive(Serialize, Deserialize, PartialEq, Debug)]
#[serde(deny_unknown_fields)]
struct S {
    a: u8,
    b: u8,
}

assert_de_tokens_error::<S>(
    &[
        Token::Struct { name: "S", len: 2 },
        Token::Str("x"),
    ],
    "unknown field `x`, expected `a` or `b`",
);