diff options
Diffstat (limited to 'third_party/rust/darling/tests/from_generics.rs')
-rw-r--r-- | third_party/rust/darling/tests/from_generics.rs | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/third_party/rust/darling/tests/from_generics.rs b/third_party/rust/darling/tests/from_generics.rs new file mode 100644 index 0000000000..e2cc99eecc --- /dev/null +++ b/third_party/rust/darling/tests/from_generics.rs @@ -0,0 +1,175 @@ +//! Tests for `FromGenerics`, and - indirectly - `FromGenericParam`. +//! These tests assume `FromTypeParam` is working and only look at whether the wrappers for magic +//! fields are working as expected. + +use darling::{ + ast::{self, GenericParamExt}, + util::{Ignored, WithOriginal}, + FromDeriveInput, FromTypeParam, Result, +}; + +#[derive(FromDeriveInput)] +#[darling(attributes(lorem))] +struct MyReceiver { + pub generics: ast::Generics<ast::GenericParam<MyTypeParam>>, +} + +#[derive(FromTypeParam)] +#[darling(attributes(lorem))] +struct MyTypeParam { + pub ident: syn::Ident, + #[darling(default)] + pub foo: bool, + pub bar: Option<String>, +} + +fn fdi<T: FromDeriveInput>(src: &str) -> Result<T> { + FromDeriveInput::from_derive_input(&syn::parse_str(src).expect("Source parses")) +} + +/// Verify that `ast::Generics` is populated correctly when there is no generics declaration +#[test] +fn no_generics() { + let rec: MyReceiver = fdi("struct Baz;").expect("Input is well-formed"); + assert!(rec.generics.where_clause.is_none()); + assert_eq!(rec.generics.params.len(), 0); +} + +#[test] +#[allow(clippy::bool_assert_comparison)] +fn expand_some() { + let rec: MyReceiver = fdi(r#" + struct Baz< + 'a, + #[lorem(foo)] T, + #[lorem(bar = "x")] U: Eq + ?Sized + >(&'a T, U); + "#) + .expect("Input is well-formed"); + assert!(rec.generics.where_clause.is_none()); + + // Make sure we've preserved the lifetime param, though we don't do anything with it. + assert!(rec.generics.params[0].as_lifetime_param().is_some()); + + let mut ty_param_iter = rec.generics.type_params(); + + let first = ty_param_iter + .next() + .expect("type_params should not be empty"); + assert!(first.bar.is_none()); + assert!(first.foo); + assert_eq!(first.ident, "T"); + + let second = ty_param_iter + .next() + .expect("type_params should have a second value"); + assert_eq!( + second + .bar + .as_ref() + .expect("Second type param should set bar"), + "x" + ); + assert_eq!(second.foo, false); + assert_eq!(second.ident, "U"); +} + +/// Verify ≤0.4.1 behavior - where `generics` had to be `syn::Generics` - keeps working. +#[test] +fn passthrough() { + #[derive(FromDeriveInput)] + struct PassthroughReceiver { + pub generics: syn::Generics, + } + + let rec: PassthroughReceiver = fdi(r#" + struct Baz< + 'a, + #[lorem(foo)] T, + #[lorem(bar = "x")] U: Eq + ?Sized + >(&'a T, U); + "#) + .expect("Input is well-formed"); + + let mut type_param_iter = rec.generics.type_params(); + assert!(type_param_iter.next().is_some()); +} + +/// Verify that `where_clause` is passed through when it exists. +/// As of 0.4.1, there is no `FromWhereClause` trait, so other types aren't supported +/// for that field. +#[test] +fn where_clause() { + let rec: MyReceiver = fdi(r#" + struct Baz< + 'a, + #[lorem(foo)] T, + #[lorem(bar = "x")] U: Eq + ?Sized + >(&'a T, U) where T: Into<String>; + "#) + .expect("Input is well-formed"); + + assert!(rec.generics.where_clause.is_some()); +} + +/// Test that `WithOriginal` works for generics. +#[test] +fn with_original() { + #[derive(FromDeriveInput)] + struct WorigReceiver { + generics: WithOriginal<ast::Generics<ast::GenericParam<MyTypeParam>>, syn::Generics>, + } + + let rec: WorigReceiver = fdi(r#" + struct Baz< + 'a, + #[lorem(foo)] T, + #[lorem(bar = "x")] U: Eq + ?Sized + >(&'a T, U) where T: Into<String>; + "#) + .expect("Input is well-formed"); + + // Make sure we haven't lost anything in the conversion + assert_eq!(rec.generics.parsed.params.len(), 3); + assert_eq!(rec.generics.original.params.len(), 3); + + let parsed_t: &MyTypeParam = rec.generics.parsed.params[1] + .as_type_param() + .expect("Second argument should be type param"); + + // Make sure the first type param in each case is T + assert_eq!(parsed_t.ident, "T"); + assert_eq!( + rec.generics + .original + .type_params() + .next() + .expect("First type param should exist") + .ident, + "T" + ); + + // Make sure we actually parsed the first type param + assert!(parsed_t.foo); + assert!(parsed_t.bar.is_none()); +} + +/// Make sure generics can be ignored +#[test] +fn ignored() { + #[derive(FromDeriveInput)] + struct IgnoredReceiver { + generics: Ignored, + } + + let rec: IgnoredReceiver = fdi(r#" + struct Baz< + 'a, + #[lorem(foo)] T, + #[lorem(bar = "x")] U: Eq + ?Sized + >(&'a T, U) where T: Into<String>; + "#) + .expect("Input is well-formed"); + + assert_eq!(Ignored, rec.generics); +} |