feat: add cawg.metadata label and test.

sdk/src/assertions/labels.rs

@@ -190,11 +190,25 @@ pub(crate) const DATABOX_STORE: &str = "c2pa.databoxes";
 /// See <https://spec.c2pa.org/specifications/specifications/2.2/specs/C2PA_Specification.html#_asset_reference>.
 pub const ASSET_REFERENCE: &str = "c2pa.asset-ref";
 
-/// Label prefix for a metadata assertion.
+/// Label prefix for a C2PA metadata assertion.
+///
+/// A C2PA metadata assertion can only be used for [specific metadata fields]
+/// as described in the C2PA Technical Specification and only if those fields
+/// are generated from a hardware or software source.
 ///
 /// See <https://spec.c2pa.org/specifications/specifications/2.2/specs/C2PA_Specification.html#_metadata>.
+///
+/// [specific metadata fields]: https://spec.c2pa.org/specifications/specifications/2.2/specs/C2PA_Specification.html#metadata_annex
 pub const METADATA: &str = "c2pa.metadata";
 
+/// Label prefix for a [CAWG metadata assertion].
+///
+/// The CAWG metadata assertion is intended for human-generated metadata
+/// and may contain metadata from any documented schema.
+///
+/// [CAWG metadata assertion]: https://cawg.io/metadata/
+pub const CAWG_METADATA: &str = "cawg.metadata";
+
 /// Must have a label that ends in '.metadata' and is preceded by an entity-specific namespace.
 /// For example, a 'com.litware.metadata' assertion would be valid.
 pub static METADATA_LABEL_REGEX: LazyLock<Regex> = LazyLock::new(|| {

sdk/src/assertions/metadata.rs

@@ -448,7 +448,13 @@ pub mod tests {
     #![allow(clippy::expect_used)]
     #![allow(clippy::unwrap_used)]
 
-    use crate::{assertion::AssertionBase, assertions::metadata::Metadata};
+    use crate::{
+        assertion::AssertionBase,
+        assertions::{
+            labels::{CAWG_METADATA, METADATA},
+            metadata::Metadata,
+        },
+    };
 
     const SPEC_EXAMPLE: &str = r#"{
         "@context" : {
@@ -485,6 +491,17 @@ pub mod tests {
         "exifEX:LensSpecification": { "@list": [ 1.55, 4.2, 1.6, 2.4 ] }
     }"#;
 
+    const CAWG_METADATA_EXAMPLE: &str = r#" {
+        "@context" : {
+            "dc" : "http://purl.org/dc/elements/1.1/"
+        },
+        "dc:created": "2025 August 13", 
+        "dc:creator": [
+             "John Doe"
+        ]
+        }
+        "#;
+
     const CUSTOM_METADATA: &str = r#" {
         "@context" : {
             "bar": "http://foo.com/bar/1.0/"
@@ -522,13 +539,13 @@ pub mod tests {
 
     #[test]
     fn metadata_from_json() {
-        let metadata = Metadata::new("c2pa.metadata", SPEC_EXAMPLE).unwrap();
+        let metadata = Metadata::new(METADATA, SPEC_EXAMPLE).unwrap();
         assert!(metadata.is_valid());
     }
 
     #[test]
     fn assertion_round_trip() {
-        let metadata = Metadata::new("c2pa.metadata", SPEC_EXAMPLE).unwrap();
+        let metadata = Metadata::new(METADATA, SPEC_EXAMPLE).unwrap();
         let assertion = metadata.to_assertion().unwrap();
         let result = Metadata::from_assertion(&assertion).unwrap();
         assert_eq!(metadata, result);
@@ -539,21 +556,27 @@ pub mod tests {
         let mut metadata = Metadata::new("custom.metadata", CUSTOM_METADATA).unwrap();
         assert!(metadata.is_valid());
         // c2pa.metadata has restrictions on fields
-        metadata.label = "c2pa.metadata".to_owned();
+        metadata.label = METADATA.to_owned();
         assert!(!metadata.is_valid());
     }
 
+    #[test]
+    fn test_cawg_metadata() {
+        let metadata = Metadata::new(CAWG_METADATA, CAWG_METADATA_EXAMPLE).unwrap();
+        assert!(metadata.is_valid());
+    }
+
     #[test]
     fn test_field_not_in_context() {
         let mut metadata = Metadata::new("custom.metadata", MISSING_CONTEXT).unwrap();
         assert!(!metadata.is_valid());
-        metadata.label = "c2pa.metadata".to_owned();
+        metadata.label = METADATA.to_owned();
         assert!(!metadata.is_valid());
     }
 
     #[test]
     fn test_uri_is_not_allowed() {
-        let mut metadata = Metadata::new("c2pa.metadata", MISMATCH_URI).unwrap();
+        let mut metadata = Metadata::new(METADATA, MISMATCH_URI).unwrap();
         assert!(!metadata.is_valid());
         // custom metadata does not have restriction on uris
         metadata.label = "custom.metadata".to_owned();
@@ -562,7 +585,7 @@ pub mod tests {
 
     #[test]
     fn test_empty_context() {
-        let metadata = Metadata::new("c2pa.metadata", EMPTY_CONTEXT).unwrap();
+        let metadata = Metadata::new(METADATA, EMPTY_CONTEXT).unwrap();
         assert!(!metadata.is_valid());
     }
 }

sdk/tests/test_builder.rs

@@ -204,10 +204,8 @@ fn test_builder_embedded_v1_otgp() -> Result<()> {
 #[test]
 fn test_dynamic_assertions_builder() -> Result<()> {
     use c2pa::{
-        // assertions::{CreativeWork, SchemaDotOrgPerson},
         dynamic_assertion::{DynamicAssertion, DynamicAssertionContent, PartialClaim},
-        Signer,
-        SigningAlg,
+        Signer, SigningAlg,
     };
     use serde::Serialize;
     #[derive(Serialize)]
@@ -220,17 +218,13 @@ fn test_dynamic_assertions_builder() -> Result<()> {
 
     impl DynamicAssertion for TestDynamicAssertion {
         fn label(&self) -> String {
-            //CreativeWork::LABEL.to_string()
             "com.mycompany.myassertion".to_string()
         }
 
         fn reserve_size(&self) -> Result<usize> {
             let assertion = TestAssertion {
                 my_tag: "some value I will replace".to_string(),
             };
-            // let assertion = CreativeWork::new()
-            //     .add_author(SchemaDotOrgPerson::new().set_name("me").unwrap())
-            //     .unwrap();
             Ok(serde_json::to_string(&assertion)?.len())
         }
 
@@ -247,9 +241,6 @@ fn test_dynamic_assertions_builder() -> Result<()> {
                 })
                 .any(|a| a.url().contains("c2pa.hash")));
 
-            // let assertion =
-            //     CreativeWork::new().add_author(SchemaDotOrgPerson::new().set_name("me")?)?;
-
             let assertion = TestAssertion {
                 my_tag: "some value I will replace".to_string(),
             };