Make handler.rs generic for anything that implements Read+Write, add unittest taking advantage of that.

Also, it'll work now for things other than UnixStreams, such as TcpStreams

server/src/handler.rs

@@ -1,18 +1,17 @@
 use crate::repository::PasswordDirectory;
 use common::request::Request;
-use std::io::{Error, Write};
-use std::os::unix::net::UnixStream;
+use std::io::{Error, Read, Write};
 
 pub const RESPONSE_NO: [u8; 4] = [0x0, 0x2, b'N', b'O'];
 pub const RESPONSE_OK: [u8; 4] = [0x0, 0x2, b'O', b'K'];
 
-pub struct Handler {
-    stream: UnixStream,
+pub struct Handler<S: Read + Write> {
+    stream: S,
     handler: PasswordDirectory,
 }
 
-impl Handler {
-    pub fn new(stream: UnixStream, handler: PasswordDirectory) -> Handler {
+impl<S: Read + Write> Handler<S> {
+    pub fn new(stream: S, handler: PasswordDirectory) -> Handler<S> {
         Handler { stream, handler }
     }
 
@@ -35,3 +34,37 @@ impl Handler {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::handler::{Handler, RESPONSE_OK};
+    use crate::repository::PasswordDirectory;
+    use common::request::Request;
+    use std::io::Cursor;
+
+    const TEST_PATH: &str = "./test_passwords";
+
+    #[test]
+    fn it_communicates_ok() {
+        let repository = PasswordDirectory::new(TEST_PATH);
+
+        let request = Request::new("bp", "some-rad-password", "ignore-this", "also-ignore-this");
+
+        let mut cursor = Cursor::new(Vec::new());
+
+        request.write_to_stream(&mut cursor).unwrap();
+
+        // Figure out where the response should end up
+        let response_position: usize = cursor.position().try_into().unwrap();
+
+        // Rewind and have the handler deal with the request
+        cursor.set_position(0);
+        Handler::new(&mut cursor, repository).handle_client();
+
+        // Extract the response, which should come after the
+        // request in the cursor buffer
+        let response = cursor.into_inner().split_off(response_position);
+
+        assert_eq!(response, RESPONSE_OK);
+    }
+}