Move tests to snapshot testing via insta
diff --git a/tests/test_asyncness.rs b/tests/test_asyncness.rs
index 3d59e6b..4d7ae7d 100644
--- a/tests/test_asyncness.rs
+++ b/tests/test_asyncness.rs
@@ -1,63 +1,20 @@
-extern crate proc_macro2;
 extern crate syn;
 
 mod features;
 
-use proc_macro2::Span;
-use syn::punctuated::Punctuated;
-use syn::{Block, Expr, ExprBlock, ExprClosure, FnDecl, Ident, ItemFn, ReturnType, Visibility};
+#[macro_use]
+mod macros;
+
+use syn::{Expr, Item};
 
 #[test]
 fn test_async_fn() {
-    let raw = "async fn process() {}";
-
-    let expected = ItemFn {
-        attrs: vec![],
-        vis: Visibility::Inherited,
-        constness: None,
-        unsafety: None,
-        asyncness: Some(Default::default()),
-        abi: None,
-        ident: Ident::new("process", Span::call_site()),
-        decl: Box::new(FnDecl {
-            fn_token: Default::default(),
-            generics: Default::default(),
-            paren_token: Default::default(),
-            inputs: Punctuated::new(),
-            variadic: None,
-            output: ReturnType::Default,
-        }),
-        block: Box::new(Block {
-            brace_token: Default::default(),
-            stmts: vec![],
-        }),
-    };
-
-    assert_eq!(expected, syn::parse_str(raw).unwrap());
+    let code = "async fn process() {}";
+    snapshot!(code as Item);
 }
 
 #[test]
 fn test_async_closure() {
-    let raw = "async || {}";
-
-    let expected = Expr::Closure(ExprClosure {
-        attrs: vec![],
-        movability: None,
-        asyncness: Some(Default::default()),
-        capture: None,
-        or1_token: Default::default(),
-        inputs: Punctuated::new(),
-        or2_token: Default::default(),
-        output: ReturnType::Default,
-        body: Box::new(Expr::Block(ExprBlock {
-            attrs: vec![],
-            label: None,
-            block: Block {
-                brace_token: Default::default(),
-                stmts: vec![],
-            },
-        })),
-    });
-
-    assert_eq!(expected, syn::parse_str(raw).unwrap());
+    let code = "async || {}";
+    snapshot!(code as Expr);
 }