Move the test server logic outside the unix server implementation

tests/server.rs

@@ -6,12 +6,49 @@
 // option. All files in the project carrying such notice may not be copied,
 // modified, or distributed except according to those terms.
 
-use std::io::{self, BufRead, BufReader, BufWriter, Write};
+use std::io::{self, BufRead, BufReader, BufWriter, Read, Write};
 use std::path::Path;
 use std::thread;
 
 use std::os::unix::net::UnixListener;
 
+/// Split lines on CRLF
+fn split_lines(lines: &str) -> Vec<String> {
+    lines
+        .trim_end()
+        .split("\r\n")
+        .map(|s| format!("{}\r\n", s))
+        .collect::<Vec<String>>()
+}
+
+/// Handle the communication for tests.
+///
+/// The communication is a list of (question, answer). If the client sends the expected question
+/// in the sequence, the answer is returned.
+fn serve_streams(
+    instream: &mut dyn Read,
+    outstream: &mut dyn Write,
+    communication: &[(&'static str, &'static str)],
+) -> io::Result<()> {
+    let mut input = BufReader::new(instream);
+    let mut output = BufWriter::new(outstream);
+    for (questions, answer) in communication.iter() {
+        for question in split_lines(questions).iter() {
+            let mut line = String::new();
+            input.read_line(&mut line)?;
+            if line != *question {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidInput,
+                    format!("read <{}> instead of <{}>", line, *question),
+                ));
+            }
+        }
+        output.write_all(answer.as_bytes())?;
+        output.flush()?;
+    }
+    Ok(())
+}
+
 /// Server traits
 pub trait Server {
     fn serve(&mut self) -> io::Result<()>;
@@ -41,36 +78,12 @@ impl UnixServer {
             communication: communication.to_vec(),
         })
     }
-
-    fn split_lines(lines: &str) -> Vec<String> {
-        lines
-            .trim_end()
-            .split("\r\n")
-            .map(|s| format!("{}\r\n", s))
-            .collect::<Vec<String>>()
-    }
 }
 
 impl Server for UnixServer {
     fn serve(&mut self) -> io::Result<()> {
-        let (stream, _) = self.listener.accept()?;
-        let mut input = BufReader::new(stream.try_clone()?);
-        let mut output = BufWriter::new(stream);
-        for (questions, answer) in self.communication.iter() {
-            for question in Self::split_lines(questions).iter() {
-                let mut line = String::new();
-                input.read_line(&mut line)?;
-                if line != *question {
-                    return Err(io::Error::new(
-                        io::ErrorKind::InvalidInput,
-                        format!("read <{}> instead of <{}>", line, *question),
-                    ));
-                }
-            }
-            output.write_all(answer.as_bytes())?;
-            output.flush()?;
-        }
-        Ok(())
+        let (mut stream, _) = self.listener.accept()?;
+        serve_streams(&mut stream.try_clone()?, &mut stream, &self.communication)
     }
 }
 
@@ -98,12 +111,10 @@ where
 #[cfg(test)]
 mod test {
 
-    use super::UnixServer;
-
     #[test]
     fn test_split_lines() {
         const ONE_LINE: &str = "one line\r\n";
-        let one_line = UnixServer::split_lines(ONE_LINE);
+        let one_line = super::split_lines(ONE_LINE);
         assert_eq!(&[ONE_LINE], one_line.as_slice());
     }
 }