Canonical empty memo test (#112)

ZcashLightClientKitTests/MemoTests.swift

@@ -49,6 +49,13 @@ class MemoTests: XCTestCase {
         XCTAssertNil(emptyMemoData.asZcashTransactionMemo())
     }
     
+    /**
+     test canonical memos
+     */
+    func testCanonicalBlankMemos() throws {
+        XCTAssertNil(Self.canonicalEmptyMemo().asZcashTransactionMemo())
+    }
+    
     /**
      *******
      * mocked memos
@@ -75,6 +82,12 @@ class MemoTests: XCTestCase {
     
     static let expectedEmojiMemoString = "💕💕💕🦓🦓🦓🛡🛡🛡"
     
+    static func canonicalEmptyMemo() -> Data {
+        var bytes = [UInt8](repeating: 0, count: 512)
+        bytes[0] = UInt8(0xF6)
+        return Data(bytes: &bytes, count: 512)
+    }
+    
     static func randomMemoData() -> Data? {
         let length: Int = 512
         var keyData = Data(count: length)