1 files changed, 90 insertions, 1 deletions
diff --git a/macros/src/fn_trait.rs b/macros/src/fn_trait.rs
index 9820f02..a52a00d 100644
--- a/macros/src/fn_trait.rs
+++ b/macros/src/fn_trait.rs
@@ -5,7 +5,7 @@ use syn::token::Paren;
 use syn::{parenthesized, parse_str, Ident, Token, TraitBound, Type};
 
 /// A function trait. `dyn Fn(u32) -> String`
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct FnTrait
 {
     pub dyn_token: Token![dyn],
@@ -84,3 +84,92 @@ impl ToTokens for FnTrait
         }
     }
 }
+
+#[cfg(test)]
+mod tests
+{
+    use std::error::Error;
+
+    use quote::{format_ident, quote};
+    use syn::token::{Dyn, RArrow};
+    use syn::{parse2, Path, PathSegment, TypePath};
+
+    use super::*;
+
+    fn create_path(segments: &[PathSegment]) -> Path
+    {
+        Path {
+            leading_colon: None,
+            segments: segments.iter().cloned().collect(),
+        }
+    }
+
+    fn create_type(path: Path) -> Type
+    {
+        Type::Path(TypePath { qself: None, path })
+    }
+
+    #[test]
+    fn can_parse_fn_trait() -> Result<(), Box<dyn Error>>
+    {
+        assert_eq!(
+            parse2::<FnTrait>(quote! {
+                dyn Fn(String, u32) -> Handle
+            })?,
+            FnTrait {
+                dyn_token: Dyn::default(),
+                trait_ident: format_ident!("Fn"),
+                paren_token: Paren::default(),
+                inputs: Punctuated::from_iter(vec![
+                    create_type(create_path(&[PathSegment::from(format_ident!(
+                        "String"
+                    ))])),
+                    create_type(create_path(&[PathSegment::from(format_ident!("u32"))]))
+                ]),
+                r_arrow_token: RArrow::default(),
+                output: create_type(create_path(&[PathSegment::from(format_ident!(
+                    "Handle"
+                ))])),
+                trait_bounds: Punctuated::new()
+            }
+        );
+
+        assert!(parse2::<FnTrait>(quote! {
+            Fn(u32) -> Handle
+        })
+        .is_err());
+
+        Ok(())
+    }
+
+    #[test]
+    fn can_parse_fn_trait_to_tokens()
+    {
+        assert_eq!(
+            FnTrait {
+                dyn_token: Dyn::default(),
+                trait_ident: format_ident!("Fn"),
+                paren_token: Paren::default(),
+                inputs: Punctuated::from_iter(vec![
+                    create_type(create_path(&[PathSegment::from(format_ident!(
+                        "Bread"
+                    ))])),
+                    create_type(create_path(&[PathSegment::from(format_ident!(
+                        "Cheese"
+                    ))])),
+                    create_type(create_path(&[PathSegment::from(format_ident!(
+                        "Tomatoes"
+                    ))]))
+                ]),
+                r_arrow_token: RArrow::default(),
+                output: create_type(create_path(&[PathSegment::from(format_ident!(
+                    "Taco"
+                ))])),
+                trait_bounds: Punctuated::new()
+            }
+            .into_token_stream()
+            .to_string(),
+            "dyn Fn (Bread , Cheese , Tomatoes) -> Taco".to_string()
+        );
+    }
+}