Add a test to confirm that #254 is fixed

Cargo.toml

@@ -36,3 +36,4 @@ serde = { version = "1.0", features = ["derive"] }
 serde_bytes = "0.11"
 serde_json = "1.0"
 option_set = "0.2"
+typetag = "0.2"

tests/254_typetag.rs

@@ -0,0 +1,188 @@
+use std::fmt::Write;
+
+use serde::{Deserialize, Serialize};
+
+#[test]
+fn typetag_usage() {
+    #[derive(Deserialize, Serialize, Debug)]
+    struct Component1 {
+        value: f32,
+        value_2: f32,
+    }
+
+    #[derive(Deserialize, Serialize, Debug)]
+    struct Component2 {
+        value: f32,
+    }
+
+    #[typetag::serde(tag = "type")]
+    trait MyTrait: std::fmt::Debug {
+        fn do_stuff(&self, buffer: &mut String);
+    }
+
+    #[typetag::serde]
+    impl MyTrait for Component1 {
+        fn do_stuff(&self, buffer: &mut String) {
+            let _ = writeln!(buffer, "{:#?}", self);
+        }
+    }
+
+    #[typetag::serde]
+    impl MyTrait for Component2 {
+        fn do_stuff(&self, buffer: &mut String) {
+            let _ = writeln!(buffer, "{:#?}", self);
+        }
+    }
+
+    #[derive(Deserialize, Serialize, Debug)]
+    struct EntityConfig {
+        name: String,
+        components: Vec<Box<dyn MyTrait>>,
+    }
+
+    let ron_config = r#"EntityConfig(
+    name: "some name",
+    components: [
+        {
+            "type": "Component1",
+            "value": 22.0,
+            "value_2": 35.0,
+        },
+        {
+            "type": "Component2",
+            "value": 3.14,
+        },
+    ],
+)"#;
+
+    let entity_config: EntityConfig = ron::from_str(ron_config).unwrap();
+
+    assert_eq!(entity_config.name, "some name");
+    assert_eq!(entity_config.components.len(), 2);
+
+    let mut buffer = String::new();
+
+    for component in &entity_config.components {
+        component.do_stuff(&mut buffer);
+    }
+
+    assert_eq!(
+        buffer,
+        r#"Component1 {
+    value: 22.0,
+    value_2: 35.0,
+}
+Component2 {
+    value: 3.14,
+}
+"#
+    );
+
+    let ron = ron::ser::to_string_pretty(
+        &entity_config,
+        ron::ser::PrettyConfig::default().struct_names(true),
+    )
+    .unwrap();
+    assert_eq!(ron, ron_config);
+}
+
+#[test]
+fn typetag_with_enum() {
+    #[derive(Deserialize, Serialize, Debug)]
+    enum SampleTestEnum {
+        Test(i32),
+        AnotherTest(f32, f32),
+    }
+
+    #[derive(Deserialize, Serialize, Debug)]
+    struct Component1 {
+        value: f32,
+        value_2: f32,
+        something: SampleTestEnum,
+    }
+
+    #[derive(Deserialize, Serialize, Debug)]
+    struct Component2 {
+        value: f32,
+    }
+
+    #[typetag::serde(tag = "type")]
+    trait MyTrait: std::fmt::Debug {
+        fn do_stuff(&self, buffer: &mut String);
+    }
+
+    #[typetag::serde]
+    impl MyTrait for Component1 {
+        fn do_stuff(&self, buffer: &mut String) {
+            match self.something {
+                SampleTestEnum::Test(number) => {
+                    let _ = writeln!(buffer, "my number: {:#?}", number);
+                }
+                SampleTestEnum::AnotherTest(float_1, float_2) => {
+                    let _ = writeln!(buffer, "f1: {:#?}, f2: {:#?}", float_1, float_2);
+                }
+            }
+        }
+    }
+
+    #[typetag::serde]
+    impl MyTrait for Component2 {
+        fn do_stuff(&self, buffer: &mut String) {
+            let _ = writeln!(buffer, "{:#?}", self.value);
+        }
+    }
+
+    #[derive(Deserialize, Serialize, Debug)]
+    struct EntityConfig {
+        name: String,
+        components: Vec<Box<dyn MyTrait>>,
+    }
+
+    let ron_config = r#"EntityConfig(
+    name: "some other name",
+    components: [
+        {
+            "type": "Component1",
+            "value": 22.0,
+            "value_2": 35.0,
+            "something": Test(22),
+        },
+        {
+            "type": "Component1",
+            "value": 12.0,
+            "value_2": 11.0,
+            "something": AnotherTest(11.0, 22.0),
+        },
+        {
+            "type": "Component2",
+            "value": 3.1,
+        },
+    ],
+)"#;
+
+    let entity_config: EntityConfig = ron::from_str(ron_config).unwrap();
+
+    assert_eq!(entity_config.name, "some other name");
+    assert_eq!(entity_config.components.len(), 3);
+
+    let mut buffer = String::new();
+
+    for component in &entity_config.components {
+        component.do_stuff(&mut buffer);
+    }
+
+    assert_eq!(
+        buffer,
+        r#"my number: 22
+f1: 11.0, f2: 22.0
+3.1
+"#
+    );
+
+    let ron = ron::ser::to_string_pretty(
+        &entity_config,
+        ron::ser::PrettyConfig::default().struct_names(true),
+    )
+    .unwrap();
+    assert_eq!(ron, ron_config);
+}