DevCRT refactor

src/emulator/devices/dev_crt.rs

@@ -1,5 +1,6 @@
 //!
 //! Legacy output device =crt
+//! Communication happens via an mpsc channel, which could be refactored away.
 //!
 //!
 use super::PMIO;
@@ -22,6 +23,7 @@ impl DevCRT {
     }
 }
 
+/// Port 0: crt output
 impl PMIO for DevCRT {
     fn read_port(&mut self, _port: u8) -> Result<i32, ()> {
         Err(()) // You can't read from the crt!
@@ -38,3 +40,29 @@ impl PMIO for DevCRT {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_dev_crt() -> Result<(), ()> {
+        let mut crt = DevCRT::default();
+        let (tx, rx) = std::sync::mpsc::channel();
+        crt.connect(tx);
+
+        // Correct port.
+        crt.write_port(0, 55)?;
+        assert!(rx.try_recv().unwrap() == 55);
+
+        // Incorrect port.
+        assert!(crt.write_port(1, 55).is_err());
+        assert!(crt.write_port(2, 55).is_err());
+        assert!(crt.write_port(3, 55).is_err());
+
+        // Incorrect port: Nothing was sent.
+        assert!(rx.try_recv().is_err());
+
+        Ok(())
+    }
+}

src/emulator/devices/tests.rs

@@ -4,26 +4,6 @@ use crate::emulator::{cpu::CPU, devices::PMIO};
 
 use super::{dev_pic::DevPIC, Bus};
 
-/// This test has the CPU output to CRT. The test listens if CRT sends the value via the channel.
-#[test]
-fn test_dev_crt() -> Result<(), ()> {
-    let mut cpu = CPU::new();
-    let mut bus = Bus::new();
-
-    let (tx, rx) = std::sync::mpsc::channel();
-    bus.crt.connect(tx);
-
-    bus.write(0, 0x02200037)?; // LOAD R1, =55
-    bus.write(1, 0x04200000)?; // OUT  R1, =0
-    cpu.tick(&mut bus);
-    cpu.tick(&mut bus);
-
-    if rx.try_recv().unwrap() == 55 {
-        return Ok(());
-    }
-    Err(())
-}
-
 ///Test KBD. The test listens for input request, sends a value and checks if it gets loaded.
 #[test]
 fn test_dev_kbd() -> Result<(), ()> {