tests: use two queues for TestingDevice.

Currently TestingDevice is a loopback device, which causes problems if the iface transmits a packet then receives.
The packet gets looped back to the interface instead of being handled by the test code.

This commit changes TestingDevice to behave more like a "virtual wire" that communicates the
interface with the testing code, with one queue for each direction.

src/iface/interface/tests/ipv4.rs

@@ -721,20 +721,14 @@ fn test_handle_igmp(#[case] medium: Medium) {
     }
 
     // General query
-    let timestamp = Instant::ZERO;
     const GENERAL_QUERY_BYTES: &[u8] = &[
         0x46, 0xc0, 0x00, 0x24, 0xed, 0xb4, 0x00, 0x00, 0x01, 0x02, 0x47, 0x43, 0xac, 0x16, 0x63,
         0x04, 0xe0, 0x00, 0x00, 0x01, 0x94, 0x04, 0x00, 0x00, 0x11, 0x64, 0xec, 0x8f, 0x00, 0x00,
         0x00, 0x00, 0x02, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         0x00,
     ];
-    {
-        // Transmit GENERAL_QUERY_BYTES into loopback
-        let tx_token = device.transmit(timestamp).unwrap();
-        tx_token.consume(GENERAL_QUERY_BYTES.len(), |buffer| {
-            buffer.copy_from_slice(GENERAL_QUERY_BYTES);
-        });
-    }
+    device.rx_queue.push_back(GENERAL_QUERY_BYTES.to_vec());
+
     // Trigger processing until all packets received through the
     // loopback have been processed, including responses to
     // GENERAL_QUERY_BYTES. Therefore `recv_all()` would return 0

src/iface/interface/tests/mod.rs

@@ -30,10 +30,8 @@ fn fill_slice(s: &mut [u8], val: u8) {
 #[allow(unused)]
 fn recv_all(device: &mut crate::tests::TestingDevice, timestamp: Instant) -> Vec<Vec<u8>> {
     let mut pkts = Vec::new();
-    while let Some((rx, _tx)) = device.receive(timestamp) {
-        rx.consume(|pkt| {
-            pkts.push(pkt.to_vec());
-        });
+    while let Some(pkt) = device.tx_queue.pop_front() {
+        pkts.push(pkt)
     }
     pkts
 }

src/iface/interface/tests/sixlowpan.rs

@@ -244,7 +244,7 @@ fn test_echo_request_sixlowpan_128_bytes() {
     );
 
     assert_eq!(
-        device.queue.pop_front().unwrap(),
+        device.tx_queue.pop_front().unwrap(),
         &[
             0x41, 0xcc, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x2, 0x2, 0x2,
             0x2, 0x2, 0x2, 0x2, 0xc0, 0xb0, 0x5, 0x4e, 0x7a, 0x11, 0x3a, 0x92, 0xfc, 0x48, 0xc2,
@@ -261,7 +261,7 @@ fn test_echo_request_sixlowpan_128_bytes() {
     iface.poll(Instant::now(), &mut device, &mut sockets);
 
     assert_eq!(
-        device.queue.pop_front().unwrap(),
+        device.tx_queue.pop_front().unwrap(),
         &[
             0x41, 0xcc, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x2, 0x2, 0x2,
             0x2, 0x2, 0x2, 0x2, 0xe0, 0xb0, 0x5, 0x4e, 0xf, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d,
@@ -415,7 +415,7 @@ In at rhoncus tortor. Cras blandit tellus diam, varius vestibulum nibh commodo n
     iface.poll(Instant::now(), &mut device, &mut sockets);
 
     assert_eq!(
-        device.queue.pop_front().unwrap(),
+        device.tx_queue.pop_front().unwrap(),
         &[
             0x41, 0xcc, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x2, 0x2, 0x2,
             0x2, 0x2, 0x2, 0x2, 0xc0, 0xb4, 0x5, 0x4e, 0x7e, 0x40, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
@@ -430,7 +430,7 @@ In at rhoncus tortor. Cras blandit tellus diam, varius vestibulum nibh commodo n
     );
 
     assert_eq!(
-        device.queue.pop_front().unwrap(),
+        device.tx_queue.pop_front().unwrap(),
         &[
             0x41, 0xcc, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x2, 0x2, 0x2,
             0x2, 0x2, 0x2, 0x2, 0xe0, 0xb4, 0x5, 0x4e, 0xf, 0x6f, 0x72, 0x74, 0x6f, 0x72, 0x2e,

src/tests.rs

@@ -1,4 +1,8 @@
+use std::collections::VecDeque;
+
 use crate::iface::*;
+use crate::phy::{self, Device, DeviceCapabilities, Medium};
+use crate::time::Instant;
 use crate::wire::*;
 
 pub(crate) fn setup<'a>(medium: Medium) -> (Interface, SocketSet<'a>, TestingDevice) {
@@ -49,16 +53,11 @@ pub(crate) fn setup<'a>(medium: Medium) -> (Interface, SocketSet<'a>, TestingDev
     (iface, SocketSet::new(vec![]), device)
 }
 
-use heapless::Deque;
-use heapless::Vec;
-
-use crate::phy::{self, Device, DeviceCapabilities, Medium};
-use crate::time::Instant;
-
 /// A testing device.
 #[derive(Debug)]
 pub struct TestingDevice {
-    pub(crate) queue: Deque<Vec<u8, 1514>, 4>,
+    pub(crate) tx_queue: VecDeque<Vec<u8>>,
+    pub(crate) rx_queue: VecDeque<Vec<u8>>,
     max_transmission_unit: usize,
     medium: Medium,
 }
@@ -71,7 +70,8 @@ impl TestingDevice {
     /// in FIFO order.
     pub fn new(medium: Medium) -> Self {
         TestingDevice {
-            queue: Deque::new(),
+            tx_queue: VecDeque::new(),
+            rx_queue: VecDeque::new(),
             max_transmission_unit: match medium {
                 #[cfg(feature = "medium-ethernet")]
                 Medium::Ethernet => 1514,
@@ -98,10 +98,10 @@ impl Device for TestingDevice {
     }
 
     fn receive(&mut self, _timestamp: Instant) -> Option<(Self::RxToken<'_>, Self::TxToken<'_>)> {
-        self.queue.pop_front().map(move |buffer| {
+        self.rx_queue.pop_front().map(move |buffer| {
             let rx = RxToken { buffer };
             let tx = TxToken {
-                queue: &mut self.queue,
+                queue: &mut self.tx_queue,
             };
             (rx, tx)
         })
@@ -109,14 +109,14 @@ impl Device for TestingDevice {
 
     fn transmit(&mut self, _timestamp: Instant) -> Option<Self::TxToken<'_>> {
         Some(TxToken {
-            queue: &mut self.queue,
+            queue: &mut self.tx_queue,
         })
     }
 }
 
 #[doc(hidden)]
 pub struct RxToken {
-    buffer: Vec<u8, 1514>,
+    buffer: Vec<u8>,
 }
 
 impl phy::RxToken for RxToken {
@@ -131,7 +131,7 @@ impl phy::RxToken for RxToken {
 #[doc(hidden)]
 #[derive(Debug)]
 pub struct TxToken<'a> {
-    queue: &'a mut Deque<Vec<u8, 1514>, 4>,
+    queue: &'a mut VecDeque<Vec<u8>>,
 }
 
 impl<'a> phy::TxToken for TxToken<'a> {
@@ -139,10 +139,9 @@ impl<'a> phy::TxToken for TxToken<'a> {
     where
         F: FnOnce(&mut [u8]) -> R,
     {
-        let mut buffer = Vec::new();
-        buffer.resize(len, 0).unwrap();
+        let mut buffer = vec![0; len];
         let result = f(&mut buffer);
-        self.queue.push_back(buffer).unwrap();
+        self.queue.push_back(buffer);
         result
     }
 }