diff --git a/src/core/input_descriptor.rs b/src/core/input_descriptor.rs
index 7857980..084ac83 100644
--- a/src/core/input_descriptor.rs
+++ b/src/core/input_descriptor.rs
@@ -650,3 +650,33 @@ pub enum ConstraintsLimitDisclosure {
     Required,
     Preferred,
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::core::presentation_definition::PresentationDefinition;
+
+    use super::*;
+
+    use anyhow::Result;
+
+    #[test]
+    fn test_input_descriptor_credential_type() -> Result<()> {
+        let definition: PresentationDefinition = serde_json::from_str(include_str!(
+            "../../tests/presentation-definition/iso.org.18013.5.1.mdl.json"
+        ))?;
+
+        let credentials = definition
+            .input_descriptors()
+            .iter()
+            .flat_map(|descriptor| descriptor.constraints().fields())
+            .filter_map(|field| field.credential_type())
+            .collect::<Vec<CredentialType>>();
+
+        assert_eq!(
+            credentials.first(),
+            Some(&"iso.org.18013.5.1.mDL".to_string())
+        );
+
+        Ok(())
+    }
+}
diff --git a/tests/presentation-definition/iso.org.18013.5.1.mdl.json b/tests/presentation-definition/iso.org.18013.5.1.mdl.json
new file mode 100644
index 0000000..58f7f0a
--- /dev/null
+++ b/tests/presentation-definition/iso.org.18013.5.1.mdl.json
@@ -0,0 +1,67 @@
+{
+  "id": "mDL_presentation_request",
+  "input_descriptors": [
+    {
+      "id": "mDL_credential",
+      "name": "Mobile Driving License",
+      "purpose": "To verify your driving privileges and age.",
+      "constraints": {
+        "fields": [
+          {
+            "path": ["$.type"],
+            "filter": {
+              "type": "array",
+              "contains": {
+                "const": "iso.org.18013.5.1.mDL"
+              }
+            }
+          },
+          {
+            "path": ["$.credentialSubject.family_name", "$.vc.credentialSubject.family_name"],
+            "purpose": "We need your family name for identification.",
+            "filter": {
+              "type": "string"
+            }
+          },
+          {
+            "path": ["$.credentialSubject.given_name", "$.vc.credentialSubject.given_name"],
+            "purpose": "We need your given name for identification.",
+            "filter": {
+              "type": "string"
+            }
+          },
+          {
+            "path": ["$.credentialSubject.birth_date", "$.vc.credentialSubject.birth_date"],
+            "purpose": "We need your birth date to verify your age.",
+            "filter": {
+              "type": "string",
+              "format": "date"
+            }
+          },
+          {
+            "path": ["$.credentialSubject.driving_privileges", "$.vc.credentialSubject.driving_privileges"],
+            "purpose": "We need to verify your driving privileges.",
+            "filter": {
+              "type": "array"
+            }
+          },
+          {
+            "path": ["$.credentialSubject.document_number", "$.vc.credentialSubject.document_number"],
+            "purpose": "We need your license number for record-keeping.",
+            "filter": {
+              "type": "string"
+            }
+          },
+          {
+            "path": ["$.credentialSubject.expiry_date", "$.vc.credentialSubject.expiry_date"],
+            "purpose": "We need to check if your license is still valid.",
+            "filter": {
+              "type": "string",
+              "format": "date"
+            }
+          }
+        ]
+      }
+    }
+  ]
+}
\ No newline at end of file