test(examples): add examples

examples/macro_rules.rs

@@ -0,0 +1,39 @@
+use serde_json::json;
+macro_rules! simple_macro {
+    (struct $name:ident { $($field:ident: $type:ty $(= $default:expr)?),*$(,)? }) => {
+        #[serde_inline_default::serde_inline_default]
+        #[derive(serde::Deserialize)]
+        struct $name {
+            $(
+                $(
+                    #[serde_inline_default($default)]
+                )?
+                $field: $type
+            ),*
+        }
+    }
+}
+
+fn main() -> Result<(), serde_json::Error> {
+    // `username` and `password` must be set when deserializing as no default value is defined for
+    // them. `secret` not as we're defining a default value for it
+    simple_macro! {
+        struct Example {
+            username: String,
+            password: String,
+            secret: String = "verysecretsecret".to_string()
+        }
+    }
+
+    let json_object = json!({
+        "username": "testuser",
+        "password": "testpassword"
+    });
+
+    let example: Example = serde_json::from_value(json_object)?;
+    assert_eq!(example.username, "testuser");
+    assert_eq!(example.password, "testpassword");
+    assert_eq!(example.secret, "verysecretsecret");
+
+    Ok(())
+}