Fix pretty print and tcp socket connect tests

This fixes #723.

src/socket/tcp.rs

@@ -731,8 +731,43 @@ impl<'a> Socket<'a> {
     /// The local port must be provided explicitly. Assuming `fn get_ephemeral_port() -> u16`
     /// allocates a port between 49152 and 65535, a connection may be established as follows:
     ///
-    /// ```rust,ignore
-    /// socket.connect((IpAddress::v4(10, 0, 0, 1), 80), get_ephemeral_port())
+    /// ```rust
+    /// # #[cfg(all(
+    /// #     feature = "medium-ethernet",
+    /// #     feature = "proto-ipv4",
+    /// # ))]
+    /// # {
+    /// # use smoltcp::socket::tcp::{Socket, SocketBuffer};
+    /// # use smoltcp::iface::{InterfaceBuilder, NeighborCache};
+    /// # use smoltcp::wire::{HardwareAddress, EthernetAddress, IpAddress, IpCidr};
+    /// #
+    /// # fn get_ephemeral_port() -> u16 {
+    /// #     49152
+    /// # }
+    /// #
+    /// # let mut socket = Socket::new(
+    /// #     SocketBuffer::new(vec![0; 1200]),
+    /// #     SocketBuffer::new(vec![0; 1200])
+    /// # );
+    /// #
+    /// # let mut ip_addrs = heapless::Vec::<IpCidr, 5>::new();
+    /// # ip_addrs
+    /// #     .push(IpCidr::new(IpAddress::v4(192, 168, 69, 1), 24))
+    /// #     .unwrap();
+    /// #
+    /// # let mut device =smoltcp::phy::Loopback::new(smoltcp::phy::Medium::Ethernet);
+    /// # let mut iface = InterfaceBuilder::new()
+    /// #     .hardware_addr(HardwareAddress::Ethernet(EthernetAddress::default()))
+    /// #     .neighbor_cache(NeighborCache::new())
+    /// #     .ip_addrs(ip_addrs)
+    /// #     .finalize(&mut device);
+    /// #
+    /// socket.connect(
+    ///     iface.context(),
+    ///     (IpAddress::v4(10, 0, 0, 1), 80),
+    ///     get_ephemeral_port()
+    /// ).unwrap();
+    /// # }
     /// ```
     ///
     /// The local address may optionally be provided.

src/wire/pretty_print.rs

@@ -7,7 +7,7 @@ easily human readable packet listings.
 
 A packet can be formatted using the `PrettyPrinter` wrapper:
 
-```rust,ignore
+```rust
 use smoltcp::wire::*;
 let buffer = vec![
     // Ethernet II
@@ -15,7 +15,7 @@ let buffer = vec![
     0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
     0x08, 0x00,
     // IPv4
-    0x45, 0x00, 0x00, 0x18,
+    0x45, 0x00, 0x00, 0x20,
     0x00, 0x00, 0x40, 0x00,
     0x40, 0x01, 0xd2, 0x79,
     0x11, 0x12, 0x13, 0x14,
@@ -25,7 +25,18 @@ let buffer = vec![
     0x12, 0x34, 0xab, 0xcd,
     0xaa, 0x00, 0x00, 0xff
 ];
-print!("{}", PrettyPrinter::<EthernetFrame<&'static [u8]>>::new("", &buffer));
+
+let result = "\
+EthernetII src=11-12-13-14-15-16 dst=01-02-03-04-05-06 type=IPv4\n\
+\\ IPv4 src=17.18.19.20 dst=33.34.35.36 proto=ICMP (checksum incorrect)\n \
+ \\ ICMPv4 echo request id=4660 seq=43981 len=4\
+";
+
+#[cfg(all(feature = "medium-ethernet", feature = "proto-ipv4"))]
+assert_eq!(
+    result,
+    &format!("{}", PrettyPrinter::<EthernetFrame<&'static [u8]>>::new("", &buffer))
+);
 ```
 */