Credential's context is a set even when a single context value is present (#1570)

* Credential's context is a set even when a single context value is present

* fix clippy warnings

* update test to check for backward compatibility

---------

Co-authored-by: Eike Haß <eike-hass@web.de>

Author: UMR1352

bindings/wasm/src/resolver/wasm_resolver.rs

@@ -175,7 +175,6 @@ impl WasmResolver {
         .await
         .map_err(WasmError::from)
         .map_err(JsValue::from)
-        .map(JsValue::from)
     });
 
     Ok(promise.unchecked_into::<PromiseIToCoreDocument>())
@@ -223,7 +222,6 @@ impl WasmResolver {
         .map(|documents| {
           documents
             .into_iter()
-            .map(JsValue::from)
             .collect::<js_sys::Array>()
             .unchecked_into::<JsValue>()
         })

identity_credential/src/credential/credential.rs

@@ -106,7 +106,7 @@ impl<T> Credential<T> {
   /// Returns a new `Credential` based on the `CredentialBuilder` configuration.
   pub fn from_builder(builder: CredentialBuilder<T>) -> Result<Self> {
     let this: Self = Self {
-      context: builder.context.into(),
+      context: OneOrMany::Many(builder.context),
       id: builder.id,
       types: builder.types.into(),
       credential_subject: builder.subject.into(),
@@ -199,9 +199,13 @@ where
 
 #[cfg(test)]
 mod tests {
+  use identity_core::common::OneOrMany;
+  use identity_core::common::Url;
   use identity_core::convert::FromJson;
 
+  use crate::credential::credential::BASE_CONTEXT;
   use crate::credential::Credential;
+  use crate::credential::Subject;
 
   const JSON1: &str = include_str!("../../tests/fixtures/credential-1.json");
   const JSON2: &str = include_str!("../../tests/fixtures/credential-2.json");
@@ -231,4 +235,22 @@ mod tests {
     let _credential: Credential = Credential::from_json(JSON11).unwrap();
     let _credential: Credential = Credential::from_json(JSON12).unwrap();
   }
+
+  #[test]
+  fn credential_with_single_context_is_list_of_contexts_with_single_item() {
+    let mut credential = Credential::builder(serde_json::Value::default())
+      .id(Url::parse("https://example.com/credentials/123").unwrap())
+      .issuer(Url::parse("https://example.com").unwrap())
+      .subject(Subject::with_id(Url::parse("https://example.com/users/123").unwrap()))
+      .build()
+      .unwrap();
+
+    assert!(matches!(credential.context, OneOrMany::Many(_)));
+    assert_eq!(credential.context.len(), 1);
+    assert!(credential.check_structure().is_ok());
+
+    // Check backward compatibility with previously created credentials.
+    credential.context = OneOrMany::One(BASE_CONTEXT.clone());
+    assert!(credential.check_structure().is_ok());
+  }
 }