diff --git a/oid4vc-core/Cargo.toml b/oid4vc-core/Cargo.toml
index a74a7a2e..681ed0bf 100644
--- a/oid4vc-core/Cargo.toml
+++ b/oid4vc-core/Cargo.toml
@@ -22,3 +22,9 @@ serde_urlencoded = "0.7.1"
 derive_more = "0.99.16"
 identity_credential.workspace = true
 futures = "0.3"
+
+[dev-dependencies]
+ed25519-dalek = "1.0.1"
+rand = "0.7"
+lazy_static = "1.4.0"
+derivative = "2.2.0"
diff --git a/oid4vc-core/src/jwt.rs b/oid4vc-core/src/jwt.rs
index 63a0a144..fdc8c025 100644
--- a/oid4vc-core/src/jwt.rs
+++ b/oid4vc-core/src/jwt.rs
@@ -75,14 +75,14 @@ where
     Ok(base64_url::encode(serde_json::to_vec(value)?.as_slice()))
 }
 
-// #[cfg(test)]
-// mod tests {
-//     use super::*;
-//     use crate::{
-//         test_utils::{MockSubject, MockVerifier},
-//         IdToken, Verify,
-//     };
-//     use serde_json::json;
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{
+        test_utils::{MockVerifier, TestSubject},
+        Verify,
+    };
+    use serde_json::{json, Value};
 
     #[tokio::test]
     async fn test_encode() {
@@ -97,26 +97,21 @@ where
         let subject = TestSubject::new("did:test:123".to_string(), "key_id".to_string()).unwrap();
         let encoded = encode(Arc::new(subject), claims).unwrap();
 
-//         });
-//         let subject = MockSubject::new("did:mock:123".to_string(), "key_id".to_string()).unwrap();
-//         let encoded = encode(Arc::new(subject), claims).await.unwrap();
+        let verifier = MockVerifier::new();
+        let (kid, algorithm) = extract_header(&encoded).unwrap();
+        let public_key = verifier.public_key(&kid).await.unwrap();
+        let decoded: Value = decode(&encoded, public_key, algorithm).unwrap();
 
-//         let verifier = MockVerifier::new();
-//         let (kid, algorithm) = extract_header(&encoded).unwrap();
-//         let public_key = verifier.public_key(&kid).await.unwrap();
-//         let decoded: IdToken = decode(&encoded, public_key, algorithm).unwrap();
-
-//         assert_eq!(
-//             decoded,
-//             IdToken::builder()
-//                 .iss("did:example:123".to_string())
-//                 .sub("did:example:123".to_string())
-//                 .aud("did:example:456".to_string())
-//                 .exp(9223372036854775807i64)
-//                 .iat(1593436422)
-//                 .nonce("nonce".to_string())
-//                 .build()
-//                 .unwrap()
-//         )
-//     }
-// }
+        assert_eq!(
+            decoded,
+            json!({
+                "iss": "did:example:123",
+                "sub": "did:example:123",
+                "aud": "did:example:456",
+                "exp": 9223372036854775807i64,
+                "iat": 1593436422,
+                "nonce": "nonce",
+            })
+        )
+    }
+}
diff --git a/oid4vc-core/src/lib.rs b/oid4vc-core/src/lib.rs
index 0f4f8a3d..e7a2b1d9 100644
--- a/oid4vc-core/src/lib.rs
+++ b/oid4vc-core/src/lib.rs
@@ -17,6 +17,9 @@ pub use rfc7519_claims::RFC7519Claims;
 use serde::Serialize;
 pub use subject_syntax_type::{DidMethod, SubjectSyntaxType};
 
+#[cfg(test)]
+mod test_utils;
+
 #[macro_export]
 macro_rules! builder_fn {
     ($name:ident, $ty:ty) => {
diff --git a/oid4vc-core/src/test_utils.rs b/oid4vc-core/src/test_utils.rs
new file mode 100644
index 00000000..97c948f2
--- /dev/null
+++ b/oid4vc-core/src/test_utils.rs
@@ -0,0 +1,68 @@
+use crate::{Sign, Subject, Verify};
+use anyhow::Result;
+use async_trait::async_trait;
+use derivative::{self, Derivative};
+use ed25519_dalek::{Keypair, Signature, Signer};
+use lazy_static::lazy_static;
+use rand::rngs::OsRng;
+
+// Keypair for mocking purposes.
+lazy_static! {
+    pub static ref TEST_KEYPAIR: Keypair = Keypair::generate(&mut OsRng);
+}
+
+#[derive(Derivative)]
+#[derivative(Default)]
+pub struct TestSubject {
+    #[derivative(Default(value = "did_url::DID::parse(\"did:test:123\").unwrap()"))]
+    pub did: did_url::DID,
+    pub key_id: String,
+}
+
+impl TestSubject {
+    pub fn new(did: String, key_id: String) -> Result<Self> {
+        Ok(TestSubject {
+            did: did_url::DID::parse(did)?,
+            key_id,
+        })
+    }
+}
+
+impl Sign for TestSubject {
+    fn key_id(&self) -> Option<String> {
+        Some(self.key_id.clone())
+    }
+
+    fn sign(&self, message: &str) -> Result<Vec<u8>> {
+        let signature: Signature = TEST_KEYPAIR.sign(message.as_bytes());
+        Ok(signature.to_bytes().to_vec())
+    }
+}
+
+#[async_trait]
+impl Verify for TestSubject {
+    async fn public_key(&self, _kid: &str) -> Result<Vec<u8>> {
+        Ok(TEST_KEYPAIR.public.to_bytes().to_vec())
+    }
+}
+
+impl Subject for TestSubject {
+    fn identifier(&self) -> Result<String> {
+        Ok(self.did.to_string())
+    }
+}
+
+pub struct MockVerifier;
+
+impl MockVerifier {
+    pub fn new() -> Self {
+        MockVerifier {}
+    }
+}
+
+#[async_trait]
+impl Verify for MockVerifier {
+    async fn public_key(&self, _kid: &str) -> Result<Vec<u8>> {
+        Ok(TEST_KEYPAIR.public.to_bytes().to_vec())
+    }
+}
diff --git a/oid4vp/tests/examples/credentials/jwt_vc.json b/oid4vp/tests/examples/credentials/jwt_vc.json
index 42944ee0..ec364f77 100644
--- a/oid4vp/tests/examples/credentials/jwt_vc.json
+++ b/oid4vp/tests/examples/credentials/jwt_vc.json
@@ -24,4 +24,4 @@
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/request/pd_ac_vc.json b/oid4vp/tests/examples/request/pd_ac_vc.json
index 568176f7..7a4fc26e 100644
--- a/oid4vp/tests/examples/request/pd_ac_vc.json
+++ b/oid4vp/tests/examples/request/pd_ac_vc.json
@@ -25,4 +25,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/request/pd_ac_vc_sd.json b/oid4vp/tests/examples/request/pd_ac_vc_sd.json
index b5483360..df26db69 100644
--- a/oid4vp/tests/examples/request/pd_ac_vc_sd.json
+++ b/oid4vp/tests/examples/request/pd_ac_vc_sd.json
@@ -1,39 +1,39 @@
 {
-    "id": "example_vc_ac_sd",
-    "input_descriptors": [
-       {
-          "id": "id_credential",
-          "format": {
-             "ac_vc": {
-                "proof_type": [
-                   "CLSignature2019"
-                ]
-             }
-          },
-          "constraints": {
-             "limit_disclosure": "required",
-             "fields": [
-                {
-                   "path": [
-                      "$.schema_id"
-                   ],
-                   "filter": {
-                      "type": "string",
-                      "const": "did:indy:idu:test:3QowxFtwciWceMFr7WbwnM:2:BasicScheme:0\\.1"
-                   }
-                },
-                {
-                   "path": [
-                      "$.values.first_name"
-                   ]
-                },
-                {
-                   "path": [
-                      "$.values.last_name"
-                   ]
-                }
-             ]
-          }
-       }
-    ]
- }
\ No newline at end of file
+   "id": "example_vc_ac_sd",
+   "input_descriptors": [
+      {
+         "id": "id_credential",
+         "format": {
+            "ac_vc": {
+               "proof_type": [
+                  "CLSignature2019"
+               ]
+            }
+         },
+         "constraints": {
+            "limit_disclosure": "required",
+            "fields": [
+               {
+                  "path": [
+                     "$.schema_id"
+                  ],
+                  "filter": {
+                     "type": "string",
+                     "const": "did:indy:idu:test:3QowxFtwciWceMFr7WbwnM:2:BasicScheme:0\\.1"
+                  }
+               },
+               {
+                  "path": [
+                     "$.values.first_name"
+                  ]
+               },
+               {
+                  "path": [
+                     "$.values.last_name"
+                  ]
+               }
+            ]
+         }
+      }
+   ]
+}
diff --git a/oid4vp/tests/examples/request/pd_jwt_vc.json b/oid4vp/tests/examples/request/pd_jwt_vc.json
index 7492cace..2abc2fef 100644
--- a/oid4vp/tests/examples/request/pd_jwt_vc.json
+++ b/oid4vp/tests/examples/request/pd_jwt_vc.json
@@ -27,4 +27,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/request/pd_ldp_vc.json b/oid4vp/tests/examples/request/pd_ldp_vc.json
index 9a09cb4b..ecb0702a 100644
--- a/oid4vp/tests/examples/request/pd_ldp_vc.json
+++ b/oid4vp/tests/examples/request/pd_ldp_vc.json
@@ -27,4 +27,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/request/pd_mdl_iso_cbor.json b/oid4vp/tests/examples/request/pd_mdl_iso_cbor.json
index 5860b59c..b459f663 100644
--- a/oid4vp/tests/examples/request/pd_mdl_iso_cbor.json
+++ b/oid4vp/tests/examples/request/pd_mdl_iso_cbor.json
@@ -54,4 +54,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/request/vp_token_type_and_claims.json b/oid4vp/tests/examples/request/vp_token_type_and_claims.json
index 4061120c..ce6b4da0 100644
--- a/oid4vp/tests/examples/request/vp_token_type_and_claims.json
+++ b/oid4vp/tests/examples/request/vp_token_type_and_claims.json
@@ -41,4 +41,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/request/vp_token_type_only.json b/oid4vp/tests/examples/request/vp_token_type_only.json
index 11579959..f1a74b1e 100644
--- a/oid4vp/tests/examples/request/vp_token_type_only.json
+++ b/oid4vp/tests/examples/request/vp_token_type_only.json
@@ -25,4 +25,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/response/presentation_submission.json b/oid4vp/tests/examples/response/presentation_submission.json
index f0ddfa2f..6761f279 100644
--- a/oid4vp/tests/examples/response/presentation_submission.json
+++ b/oid4vp/tests/examples/response/presentation_submission.json
@@ -12,4 +12,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/response/presentation_submission_multiple_vps.json b/oid4vp/tests/examples/response/presentation_submission_multiple_vps.json
index 30c0128d..e9e95d36 100644
--- a/oid4vp/tests/examples/response/presentation_submission_multiple_vps.json
+++ b/oid4vp/tests/examples/response/presentation_submission_multiple_vps.json
@@ -21,4 +21,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/response/ps_ac_vc_sd.json b/oid4vp/tests/examples/response/ps_ac_vc_sd.json
index 59eee37c..1f209413 100644
--- a/oid4vp/tests/examples/response/ps_ac_vc_sd.json
+++ b/oid4vp/tests/examples/response/ps_ac_vc_sd.json
@@ -12,4 +12,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/response/ps_jwt_vc.json b/oid4vp/tests/examples/response/ps_jwt_vc.json
index bb16f172..fb018c8d 100644
--- a/oid4vp/tests/examples/response/ps_jwt_vc.json
+++ b/oid4vp/tests/examples/response/ps_jwt_vc.json
@@ -2,14 +2,14 @@
     "definition_id": "example_jwt_vc",
     "id": "example_jwt_vc_presentation_submission",
     "descriptor_map": [
-      {
-        "id": "id_credential",
-        "path": "$",
-        "format": "jwt_vp_json",
-        "path_nested": {
-          "path": "$.vp.verifiableCredential[0]",
-          "format": "jwt_vc_json"
+        {
+            "id": "id_credential",
+            "path": "$",
+            "format": "jwt_vp_json",
+            "path_nested": {
+                "path": "$.vp.verifiableCredential[0]",
+                "format": "jwt_vc_json"
+            }
         }
-      }
     ]
-  }
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/response/ps_ldp_vc.json b/oid4vp/tests/examples/response/ps_ldp_vc.json
index a859d56d..40cc14f9 100644
--- a/oid4vp/tests/examples/response/ps_ldp_vc.json
+++ b/oid4vp/tests/examples/response/ps_ldp_vc.json
@@ -12,4 +12,4 @@
             }
         }
     ]
-}
\ No newline at end of file
+}
diff --git a/oid4vp/tests/examples/response/ps_mdl_iso_cbor.json b/oid4vp/tests/examples/response/ps_mdl_iso_cbor.json
index 4d0e6c8f..7435928b 100644
--- a/oid4vp/tests/examples/response/ps_mdl_iso_cbor.json
+++ b/oid4vp/tests/examples/response/ps_mdl_iso_cbor.json
@@ -8,4 +8,4 @@
             "path": "$"
         }
     ]
-}
\ No newline at end of file
+}