add AuthenticatorData tests

Author: marius-se

Tests/WebAuthnTests/ParsedAuthenticatorAttestationResponseTests.swift renamed to Tests/WebAuthnTests/Ceremonies/Registration/ParsedAuthenticatorAttestationResponseTests.swift

@@ -0,0 +1,40 @@
+import XCTest
+@testable import WebAuthn
+
+// swiftlint:disable line_length
+
+final class AuthenticatorDataTests: XCTestCase {
+    // Information about authenticator data: https://w3c.github.io/webauthn/#authenticator-data
+
+    func testInitFromBytesFailsIfAuthDataIsTooShort() throws {
+        let tooManyBytes = [UInt8](repeating: 1, count: 36)
+        XCTAssertThrowsError(try AuthenticatorData(bytes: Data(tooManyBytes))) { error in
+            XCTAssertEqual(error as? WebAuthnError, .authDataTooShort)
+        }
+    }
+
+    func testInitFromBytesFailsIfAttestedCredentialDataFlagIsSetButDataIsActuallyNotThere() throws {
+        let rpIdHash = [UInt8](repeating: 0, count: 32)
+        let flagsByte: [UInt8] = [0b01000000] // "attested credential data included"
+        let signCount = [UInt8](repeating: 0, count: 4)
+
+        let bytes = rpIdHash + flagsByte + signCount
+
+        XCTAssertThrowsError(try AuthenticatorData(bytes: Data(bytes))) { error in
+            XCTAssertEqual(error as? WebAuthnError, .attestedCredentialDataMissing)
+        }
+    }
+
+    func testInitFromBytesFailsIfAttestedCredentialDataFlagIsNotSetButThereActuallyIsData() throws {
+        let rpIdHash = [UInt8](repeating: 0, count: 32)
+        let flagsByte: [UInt8] = [0b00000000] // "attested credential data included"
+        let signCount = [UInt8](repeating: 0, count: 4)
+        let fakeAttestedCredentialData: [UInt8] = [UInt8](repeating: 0, count: 4)
+
+        let bytes = rpIdHash + flagsByte + signCount + fakeAttestedCredentialData
+
+        XCTAssertThrowsError(try AuthenticatorData(bytes: Data(bytes))) { error in
+            XCTAssertEqual(error as? WebAuthnError, .attestedCredentialFlagNotSet)
+        }
+    }
+}