1 files changed, 11 insertions, 0 deletions
diff --git a/src/error.rs b/src/error.rs
index 89c4c82..3f60af2 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -9,6 +9,8 @@ use std::result;
 pub enum Error {
     /// An error reported by the Nitrokey device in the response packet.
     CommandError(CommandError),
+    /// Placeholder for testing.
+    CommunicationError(CommunicationError),
 }
 
 impl From<CommandError> for Error {
@@ -21,6 +23,7 @@ impl error::Error for Error {
     fn source(&self) -> Option<&(dyn error::Error + 'static)> {
         match *self {
             Error::CommandError(ref err) => Some(err),
+            Error::CommunicationError(_) => None,
         }
     }
 }
@@ -29,6 +32,7 @@ impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             Error::CommandError(ref err) => write!(f, "Command error: {}", err),
+            Error::CommunicationError(_) => write!(f, "Placeholder"),
         }
     }
 }
@@ -78,6 +82,13 @@ pub enum CommandError {
     RngError,
 }
 
+/// Placeholder for testing.
+#[derive(Debug)]
+pub enum CommunicationError {
+    /// Placeholder for testing.
+    NotConnected,
+}
+
 impl CommandError {
     fn as_str(&self) -> borrow::Cow<'static, str> {
         match *self {