add a test for parsing PortableDid (decentralized-identity#50)

* add a test for parsing PortableDid

* remove portable did test in Web5Tests; add  portable did test in Web5TestVectors

* Update portabledid metadata to required

Author: AlexHsieh

Sources/Web5/Dids/BearerDID.swift

@@ -105,7 +105,7 @@ public struct BearerDID {
             uri: did.uri,
             document: document,
             privateKeys: privateKeys,
-            metadata: metadata
+            metadata: metadata ?? [:]
         )
     }
 }

Sources/Web5/Dids/PortableDID.swift

@@ -20,5 +20,5 @@ public struct PortableDID: Codable {
     let privateKeys: [Jwk]
 
     /// Additional DID method specific information to be included
-    let metadata: Metadata?
+    let metadata: Metadata
 }

Tests/Web5TestVectors/Web5TestVectorsPortableDid.swift

@@ -0,0 +1,41 @@
+import XCTest
+import AnyCodable
+@testable import Web5
+
+final class Web5TestVectorsPortableDid: XCTestCase {
+
+    func test_parse() throws {
+        
+        struct Output: Codable {}
+        /// TestVector Input could not be optional. 
+        /// We need an optional structure to temporary store incomplete did json
+        struct OptionalPortableDid: Codable {
+            typealias Metadata = [String: AnyCodable]
+            let uri: String?
+            let document: DIDDocument?
+            let privateKeys: [Jwk]?
+            let metadata: Metadata?
+        }
+
+        let testVector = try TestVector<OptionalPortableDid, Output>(
+            fileName: "parse",
+            subdirectory: "test-vectors/portable_did"
+        )
+
+        testVector.run { vector in
+
+            guard let isError: Bool = vector.errors else {
+                return XCTFail("Missing `errors` property")
+            }
+
+            let data = try JSONEncoder().encode(vector.input)
+            
+            if(isError) {
+                XCTAssertThrowsError(try JSONDecoder().decode(PortableDID.self, from: data))
+            } else {
+                let dataModel = try JSONDecoder().decode(PortableDID.self, from: data)
+                XCTAssertNotNil(dataModel);
+            }
+        }
+    }
+}

Tests/Web5Tests/Dids/BearerDIDTests.swift

@@ -12,7 +12,7 @@ final class BearerDIDTests: XCTestCase {
         XCTAssertNoDifference(portableDID.uri, didJWK.uri)
         XCTAssertNoDifference(portableDID.document, didJWK.document)
         XCTAssertNoDifference(portableDID.privateKeys.count, 1)
-        XCTAssertNil(portableDID.metadata)
+        XCTAssertNoDifference(portableDID.metadata, [:])
     }
 
     func test_getSigner() throws {