     
     func testDiscovery() {
         
+        // MTU Exchange
         do {
             
             let data: [UInt8] = [2, 185, 0]

            XCTAssertEqual(pdu.requestOpcode, .readByGroupTypeRequest)
        }
        
        do {
            
            let data: [UInt8] = [8, 1, 0, 6, 0, 3, 40]

                                                       value: Data(pdu.data[0].value),
                                                       permissions: [.read])
                
                guard let declaration = GATTDatabase.CharacteristicDeclarationAttribute(attribute: attribute)
                    else { XCTFail(); return }
                
                XCTAssertEqual(declaration.attribute.value, attribute.value)
                XCTAssertEqual(declaration.uuid.rawValue, "2BE58BC4-7DF2-4CB1-9350-CDA44533EA99")
                XCTAssertEqual(declaration.valueHandle, 3)
                XCTAssertEqual(declaration.properties, [.notify])
            }
            
            do {
