50 lines
1.1 KiB
Rust
50 lines
1.1 KiB
Rust
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use std::collections::BTreeSet;
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use darling::{Error, FromDeriveInput, Result};
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use syn::parse_quote;
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fn field_names(data: &syn::Data) -> Result<BTreeSet<String>> {
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let fields = match data {
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syn::Data::Struct(data) => data.fields.iter(),
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syn::Data::Enum(_) => return Err(Error::custom("Expected struct or union")),
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syn::Data::Union(data) => data.fields.named.iter(),
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};
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Ok(fields
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.filter_map(|f| f.ident.clone())
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.map(|i| i.to_string())
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.collect())
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}
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#[derive(FromDeriveInput)]
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#[darling(attributes(a), forward_attrs)]
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struct Receiver {
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#[darling(with = field_names)]
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data: BTreeSet<String>,
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}
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#[test]
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fn succeeds_on_no_fields() {
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let di = Receiver::from_derive_input(&parse_quote! {
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struct Demo;
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})
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.unwrap();
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assert!(di.data.is_empty());
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}
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#[test]
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fn succeeds_on_valid_input() {
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let di = Receiver::from_derive_input(&parse_quote! {
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struct Demo {
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hello: String,
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world: String,
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}
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})
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.unwrap();
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assert_eq!(di.data.len(), 2);
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assert!(di.data.contains("hello"));
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assert!(di.data.contains("world"));
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}
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