diff --git a/src/futures/write/generic/decoder.rs b/src/futures/write/generic/decoder.rs
index 7edf741e..f82f8751 100644
--- a/src/futures/write/generic/decoder.rs
+++ b/src/futures/write/generic/decoder.rs
@@ -151,7 +151,7 @@ impl<W: AsyncWrite, D: Decode> AsyncWrite for Decoder<W, D> {
 
     fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
         ready!(self.as_mut().do_poll_flush(cx))?;
-        ready!(self.project().writer.as_mut().poll_close(cx))?;
+        ready!(self.project().writer.as_mut().poll_flush(cx))?;
         Poll::Ready(Ok(()))
     }
 
diff --git a/tests/utils/mod.rs b/tests/utils/mod.rs
index df342a50..f73f8d21 100644
--- a/tests/utils/mod.rs
+++ b/tests/utils/mod.rs
@@ -1,5 +1,7 @@
 #![allow(dead_code, unused_macros)] // Different tests use a different subset of functions
 
+mod track_closed;
+
 use bytes::Bytes;
 use futures::{
     io::AsyncBufRead,
@@ -61,6 +63,7 @@ impl From<Vec<Vec<u8>>> for InputStream {
 }
 
 pub mod prelude {
+    use super::track_closed::TrackClosedExt as _;
     pub use async_compression::Level;
     pub use bytes::Bytes;
     pub use futures::{
@@ -109,13 +112,17 @@ pub mod prelude {
         {
             let mut test_writer = (&mut output)
                 .limited_write(limit)
-                .interleave_pending_write();
-            let mut writer = create_writer(&mut test_writer);
-            for chunk in input {
-                block_on(writer.write_all(chunk)).unwrap();
-                block_on(writer.flush()).unwrap();
+                .interleave_pending_write()
+                .track_closed();
+            {
+                let mut writer = create_writer(&mut test_writer);
+                for chunk in input {
+                    block_on(writer.write_all(chunk)).unwrap();
+                    block_on(writer.flush()).unwrap();
+                }
+                block_on(writer.close()).unwrap();
             }
-            block_on(writer.close()).unwrap();
+            assert!(test_writer.is_closed());
         }
         output
     }
diff --git a/tests/utils/track_closed.rs b/tests/utils/track_closed.rs
new file mode 100644
index 00000000..93e12d42
--- /dev/null
+++ b/tests/utils/track_closed.rs
@@ -0,0 +1,63 @@
+use core::{
+    pin::Pin,
+    task::{Context, Poll},
+};
+use futures::io::AsyncWrite;
+use std::io::{IoSlice, Result};
+
+pub trait TrackClosedExt: AsyncWrite {
+    fn track_closed(self) -> TrackClosed<Self>
+    where
+        Self: Sized + Unpin,
+    {
+        TrackClosed {
+            inner: self,
+            closed: false,
+        }
+    }
+}
+
+impl<W: AsyncWrite> TrackClosedExt for W {}
+
+pub struct TrackClosed<W: AsyncWrite + Unpin> {
+    inner: W,
+    closed: bool,
+}
+
+impl<W: AsyncWrite + Unpin> TrackClosed<W> {
+    pub fn is_closed(&self) -> bool {
+        self.closed
+    }
+}
+
+impl<W: AsyncWrite + Unpin> AsyncWrite for TrackClosed<W> {
+    fn poll_write(mut self: Pin<&mut Self>, cx: &mut Context, buf: &[u8]) -> Poll<Result<usize>> {
+        assert!(!self.closed);
+        Pin::new(&mut self.inner).poll_write(cx, buf)
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<()>> {
+        assert!(!self.closed);
+        Pin::new(&mut self.inner).poll_flush(cx)
+    }
+
+    fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<()>> {
+        assert!(!self.closed);
+        match Pin::new(&mut self.inner).poll_close(cx) {
+            Poll::Ready(Ok(())) => {
+                self.closed = true;
+                Poll::Ready(Ok(()))
+            }
+            other => other,
+        }
+    }
+
+    fn poll_write_vectored(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context,
+        bufs: &[IoSlice],
+    ) -> Poll<Result<usize>> {
+        assert!(!self.closed);
+        Pin::new(&mut self.inner).poll_write_vectored(cx, bufs)
+    }
+}