Add required array element constraints

crates/decodal-derive/tests/derive.rs

@@ -12,6 +12,18 @@ struct Service {
     tags: Vec<String>,
 }
 
+#[derive(Debug, PartialEq, Decodal)]
+struct Worker {
+    name: String,
+    #[decodal(default = true)]
+    enabled: bool,
+}
+
+#[derive(Debug, PartialEq, Decodal)]
+struct Fleet {
+    workers: Vec<Worker>,
+}
+
 #[test]
 fn derives_schema_and_decode() {
     let mut engine = Engine::new(EmptyLoader);
@@ -77,3 +89,62 @@ fn decode_reports_field_path() {
     let error = Service::decodal_decode(&data).unwrap_err();
     assert_eq!(error.path, "name");
 }
+
+#[test]
+fn vec_schema_rejects_invalid_element_before_decode() {
+    let mut engine = Engine::new(EmptyLoader);
+    engine
+        .bind_global("Service", Service::decodal_schema())
+        .unwrap();
+    let module = engine
+        .add_root_source(
+            "test",
+            "test",
+            r#"
+            Service & {
+              name = "api";
+              port = 9443;
+              tags = ["web", 1];
+            }
+            "#,
+        )
+        .unwrap();
+    let error = engine.eval_module(module).unwrap_err();
+    assert!(
+        error
+            .labels
+            .iter()
+            .any(|label| label.message.contains("array element [1]"))
+    );
+}
+
+#[test]
+fn vec_schema_applies_nested_struct_defaults() {
+    let mut engine = Engine::new(EmptyLoader);
+    engine
+        .bind_global("Fleet", Fleet::decodal_schema())
+        .unwrap();
+    let module = engine
+        .add_root_source(
+            "test",
+            "test",
+            r#"
+            Fleet & {
+              workers = [{ name = "api"; }];
+            }
+            "#,
+        )
+        .unwrap();
+    let value = engine.eval_module(module).unwrap();
+    let data = engine.materialize(&value).unwrap();
+    let fleet = Fleet::decodal_decode(&data).unwrap();
+    assert_eq!(
+        fleet,
+        Fleet {
+            workers: vec![Worker {
+                name: "api".into(),
+                enabled: true,
+            }],
+        }
+    );
+}