Add some tests

1 files changed, 20 insertions, 11 deletions

diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 5b19c0b81bd..f7b26e5888d 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -541,7 +541,7 @@ impl<W: Write> BufWriter<W> {
     /// ```
     #[unstable(feature = "bufreader_buffer", issue = "45323")]
     pub fn buffer(&self) -> &[u8] {
-        &self.buf[..]
+        &self.buf
     }
 
     /// Unwraps this `BufWriter`, returning the underlying writer.
@@ -984,31 +984,31 @@ mod tests {
         let mut buf = [0, 0, 0];
         let nread = reader.read(&mut buf);
         assert_eq!(nread.unwrap(), 3);
-        let b: &[_] = &[5, 6, 7];
-        assert_eq!(buf, b);
+        assert_eq!(buf, [5, 6, 7]);
+        assert_eq!(*reader.buffer(), []);
 
         let mut buf = [0, 0];
         let nread = reader.read(&mut buf);
         assert_eq!(nread.unwrap(), 2);
-        let b: &[_] = &[0, 1];
-        assert_eq!(buf, b);
+        assert_eq!(buf, [0, 1]);
+        assert_eq!(*reader.buffer(), []);
 
         let mut buf = [0];
         let nread = reader.read(&mut buf);
         assert_eq!(nread.unwrap(), 1);
-        let b: &[_] = &[2];
-        assert_eq!(buf, b);
+        assert_eq!(buf, [2]);
+        assert_eq!(*reader.buffer(), [3]);
 
         let mut buf = [0, 0, 0];
         let nread = reader.read(&mut buf);
         assert_eq!(nread.unwrap(), 1);
-        let b: &[_] = &[3, 0, 0];
-        assert_eq!(buf, b);
+        assert_eq!(buf, [3, 0, 0]);
+        assert_eq!(*reader.buffer(), []);
 
         let nread = reader.read(&mut buf);
         assert_eq!(nread.unwrap(), 1);
-        let b: &[_] = &[4, 0, 0];
-        assert_eq!(buf, b);
+        assert_eq!(buf, [4, 0, 0]);
+        assert_eq!(*reader.buffer(), []);
 
         assert_eq!(reader.read(&mut buf).unwrap(), 0);
     }
@@ -1097,31 +1097,40 @@ mod tests {
         let mut writer = BufWriter::with_capacity(2, inner);
 
         writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.buffer(), []);
         assert_eq!(*writer.get_ref(), [0, 1]);
 
         writer.write(&[2]).unwrap();
+        assert_eq!(*writer.buffer(), [2]);
         assert_eq!(*writer.get_ref(), [0, 1]);
 
         writer.write(&[3]).unwrap();
+        assert_eq!(*writer.buffer(), [2, 3]);
         assert_eq!(*writer.get_ref(), [0, 1]);
 
         writer.flush().unwrap();
+        assert_eq!(*writer.buffer(), []);
         assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
 
         writer.write(&[4]).unwrap();
         writer.write(&[5]).unwrap();
+        assert_eq!(*writer.buffer(), [4, 5]);
         assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
 
         writer.write(&[6]).unwrap();
+        assert_eq!(*writer.buffer(), [6]);
         assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
 
         writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.buffer(), []);
         assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
 
         writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.buffer(), []);
         assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
 
         writer.flush().unwrap();
+        assert_eq!(*writer.buffer(), []);
         assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
     }