add another test to validate EOF behaviour

Author: Byron

gix-packetline/src/read/async_io.rs

@@ -138,7 +138,8 @@ where
         }
     }
 
-    /// Peek the next packet line without consuming it.
+    /// Peek the next packet line without consuming it. Returns `None` if a stop-packet or an error
+    /// was encountered.
     ///
     /// Multiple calls to peek will return the same packet line, if there is one.
     pub async fn peek_line(&mut self) -> Option<io::Result<Result<PacketLineRef<'_>, decode::Error>>> {

gix-packetline/src/read/blocking_io.rs

@@ -132,7 +132,8 @@ where
         }
     }
 
-    /// Peek the next packet line without consuming it.
+    /// Peek the next packet line without consuming it. Returns `None` if a stop-packet or an error
+    /// was encountered.
     ///
     /// Multiple calls to peek will return the same packet line, if there is one.
     pub fn peek_line(&mut self) -> Option<io::Result<Result<PacketLineRef<'_>, decode::Error>>> {

gix-packetline/tests/read/mod.rs

@@ -72,6 +72,28 @@ pub mod streaming_peek_iter {
         Ok(())
     }
 
+    #[maybe_async::test(feature = "blocking-io", async(feature = "async-io", async_std::test))]
+    async fn peek_eof_is_none() -> crate::Result {
+        let mut rd =
+            gix_packetline::StreamingPeekableIter::new(&b"0005a0009ERR e0000"[..], &[PacketLineRef::Flush], false);
+        rd.fail_on_err_lines(false);
+        let res = rd.peek_line().await;
+        assert_eq!(res.expect("line")??, PacketLineRef::Data(b"a"));
+        rd.read_line().await;
+        let res = rd.peek_line().await;
+        assert_eq!(
+            res.expect("line")??,
+            PacketLineRef::Data(b"ERR e"),
+            "we read the ERR but it's not interpreted as such"
+        );
+        rd.read_line().await;
+
+        let res = rd.peek_line().await;
+        assert!(res.is_none(), "we peek into the flush packet, which is EOF");
+        assert_eq!(rd.stopped_at(), Some(PacketLineRef::Flush));
+        Ok(())
+    }
+
     #[maybe_async::test(feature = "blocking-io", async(feature = "async-io", async_std::test))]
     async fn peek_non_data() -> crate::Result {
         let mut rd =