1 files changed, 516 insertions, 0 deletions
diff --git a/library/std/src/io/cursor/tests.rs b/library/std/src/io/cursor/tests.rs
new file mode 100644
index 00000000000..80d88ca66f6
--- /dev/null
+++ b/library/std/src/io/cursor/tests.rs
@@ -0,0 +1,516 @@
+use crate::io::prelude::*;
+use crate::io::{Cursor, IoSlice, IoSliceMut, SeekFrom};
+
+#[test]
+fn test_vec_writer() {
+    let mut writer = Vec::new();
+    assert_eq!(writer.write(&[0]).unwrap(), 1);
+    assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+    assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+    assert_eq!(
+        writer
+            .write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],)
+            .unwrap(),
+        3
+    );
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    assert_eq!(writer, b);
+}
+
+#[test]
+fn test_mem_writer() {
+    let mut writer = Cursor::new(Vec::new());
+    assert_eq!(writer.write(&[0]).unwrap(), 1);
+    assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+    assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+    assert_eq!(
+        writer
+            .write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],)
+            .unwrap(),
+        3
+    );
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    assert_eq!(&writer.get_ref()[..], b);
+}
+
+#[test]
+fn test_mem_mut_writer() {
+    let mut vec = Vec::new();
+    let mut writer = Cursor::new(&mut vec);
+    assert_eq!(writer.write(&[0]).unwrap(), 1);
+    assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+    assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+    assert_eq!(
+        writer
+            .write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],)
+            .unwrap(),
+        3
+    );
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    assert_eq!(&writer.get_ref()[..], b);
+}
+
+#[test]
+fn test_box_slice_writer() {
+    let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+    assert_eq!(writer.position(), 0);
+    assert_eq!(writer.write(&[0]).unwrap(), 1);
+    assert_eq!(writer.position(), 1);
+    assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+    assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+    assert_eq!(writer.position(), 8);
+    assert_eq!(writer.write(&[]).unwrap(), 0);
+    assert_eq!(writer.position(), 8);
+
+    assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+    assert_eq!(writer.write(&[10]).unwrap(), 0);
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+    assert_eq!(&**writer.get_ref(), b);
+}
+
+#[test]
+fn test_box_slice_writer_vectored() {
+    let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+    assert_eq!(writer.position(), 0);
+    assert_eq!(writer.write_vectored(&[IoSlice::new(&[0])]).unwrap(), 1);
+    assert_eq!(writer.position(), 1);
+    assert_eq!(
+        writer.write_vectored(&[IoSlice::new(&[1, 2, 3]), IoSlice::new(&[4, 5, 6, 7]),]).unwrap(),
+        7,
+    );
+    assert_eq!(writer.position(), 8);
+    assert_eq!(writer.write_vectored(&[]).unwrap(), 0);
+    assert_eq!(writer.position(), 8);
+
+    assert_eq!(writer.write_vectored(&[IoSlice::new(&[8, 9])]).unwrap(), 1);
+    assert_eq!(writer.write_vectored(&[IoSlice::new(&[10])]).unwrap(), 0);
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+    assert_eq!(&**writer.get_ref(), b);
+}
+
+#[test]
+fn test_buf_writer() {
+    let mut buf = [0 as u8; 9];
+    {
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+    }
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+    assert_eq!(buf, b);
+}
+
+#[test]
+fn test_buf_writer_vectored() {
+    let mut buf = [0 as u8; 9];
+    {
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write_vectored(&[IoSlice::new(&[0])]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(
+            writer
+                .write_vectored(&[IoSlice::new(&[1, 2, 3]), IoSlice::new(&[4, 5, 6, 7])],)
+                .unwrap(),
+            7,
+        );
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write_vectored(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write_vectored(&[IoSlice::new(&[8, 9])]).unwrap(), 1);
+        assert_eq!(writer.write_vectored(&[IoSlice::new(&[10])]).unwrap(), 0);
+    }
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+    assert_eq!(buf, b);
+}
+
+#[test]
+fn test_buf_writer_seek() {
+    let mut buf = [0 as u8; 8];
+    {
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+
+        assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+        assert_eq!(writer.position(), 2);
+        assert_eq!(writer.write(&[2]).unwrap(), 1);
+        assert_eq!(writer.position(), 3);
+
+        assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[3]).unwrap(), 1);
+        assert_eq!(writer.position(), 2);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.position(), 7);
+        assert_eq!(writer.write(&[4]).unwrap(), 1);
+        assert_eq!(writer.position(), 8);
+    }
+    let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+    assert_eq!(buf, b);
+}
+
+#[test]
+fn test_buf_writer_error() {
+    let mut buf = [0 as u8; 2];
+    let mut writer = Cursor::new(&mut buf[..]);
+    assert_eq!(writer.write(&[0]).unwrap(), 1);
+    assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+    assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+}
+
+#[test]
+fn test_mem_reader() {
+    let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
+    let mut buf = [];
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    assert_eq!(reader.position(), 0);
+    let mut buf = [0];
+    assert_eq!(reader.read(&mut buf).unwrap(), 1);
+    assert_eq!(reader.position(), 1);
+    let b: &[_] = &[0];
+    assert_eq!(buf, b);
+    let mut buf = [0; 4];
+    assert_eq!(reader.read(&mut buf).unwrap(), 4);
+    assert_eq!(reader.position(), 5);
+    let b: &[_] = &[1, 2, 3, 4];
+    assert_eq!(buf, b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 3);
+    let b: &[_] = &[5, 6, 7];
+    assert_eq!(&buf[..3], b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn test_mem_reader_vectored() {
+    let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
+    let mut buf = [];
+    assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0);
+    assert_eq!(reader.position(), 0);
+    let mut buf = [0];
+    assert_eq!(
+        reader.read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]).unwrap(),
+        1,
+    );
+    assert_eq!(reader.position(), 1);
+    let b: &[_] = &[0];
+    assert_eq!(buf, b);
+    let mut buf1 = [0; 4];
+    let mut buf2 = [0; 4];
+    assert_eq!(
+        reader
+            .read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2),])
+            .unwrap(),
+        7,
+    );
+    let b1: &[_] = &[1, 2, 3, 4];
+    let b2: &[_] = &[5, 6, 7];
+    assert_eq!(buf1, b1);
+    assert_eq!(&buf2[..3], b2);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn test_boxed_slice_reader() {
+    let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice());
+    let mut buf = [];
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    assert_eq!(reader.position(), 0);
+    let mut buf = [0];
+    assert_eq!(reader.read(&mut buf).unwrap(), 1);
+    assert_eq!(reader.position(), 1);
+    let b: &[_] = &[0];
+    assert_eq!(buf, b);
+    let mut buf = [0; 4];
+    assert_eq!(reader.read(&mut buf).unwrap(), 4);
+    assert_eq!(reader.position(), 5);
+    let b: &[_] = &[1, 2, 3, 4];
+    assert_eq!(buf, b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 3);
+    let b: &[_] = &[5, 6, 7];
+    assert_eq!(&buf[..3], b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn test_boxed_slice_reader_vectored() {
+    let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice());
+    let mut buf = [];
+    assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0);
+    assert_eq!(reader.position(), 0);
+    let mut buf = [0];
+    assert_eq!(
+        reader.read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]).unwrap(),
+        1,
+    );
+    assert_eq!(reader.position(), 1);
+    let b: &[_] = &[0];
+    assert_eq!(buf, b);
+    let mut buf1 = [0; 4];
+    let mut buf2 = [0; 4];
+    assert_eq!(
+        reader
+            .read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)],)
+            .unwrap(),
+        7,
+    );
+    let b1: &[_] = &[1, 2, 3, 4];
+    let b2: &[_] = &[5, 6, 7];
+    assert_eq!(buf1, b1);
+    assert_eq!(&buf2[..3], b2);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn read_to_end() {
+    let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
+    let mut v = Vec::new();
+    reader.read_to_end(&mut v).unwrap();
+    assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+}
+
+#[test]
+fn test_slice_reader() {
+    let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+    let reader = &mut &in_buf[..];
+    let mut buf = [];
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    let mut buf = [0];
+    assert_eq!(reader.read(&mut buf).unwrap(), 1);
+    assert_eq!(reader.len(), 7);
+    let b: &[_] = &[0];
+    assert_eq!(&buf[..], b);
+    let mut buf = [0; 4];
+    assert_eq!(reader.read(&mut buf).unwrap(), 4);
+    assert_eq!(reader.len(), 3);
+    let b: &[_] = &[1, 2, 3, 4];
+    assert_eq!(&buf[..], b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 3);
+    let b: &[_] = &[5, 6, 7];
+    assert_eq!(&buf[..3], b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn test_slice_reader_vectored() {
+    let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+    let reader = &mut &in_buf[..];
+    let mut buf = [];
+    assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0);
+    let mut buf = [0];
+    assert_eq!(
+        reader.read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]).unwrap(),
+        1,
+    );
+    assert_eq!(reader.len(), 7);
+    let b: &[_] = &[0];
+    assert_eq!(buf, b);
+    let mut buf1 = [0; 4];
+    let mut buf2 = [0; 4];
+    assert_eq!(
+        reader
+            .read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)],)
+            .unwrap(),
+        7,
+    );
+    let b1: &[_] = &[1, 2, 3, 4];
+    let b2: &[_] = &[5, 6, 7];
+    assert_eq!(buf1, b1);
+    assert_eq!(&buf2[..3], b2);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn test_read_exact() {
+    let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+    let reader = &mut &in_buf[..];
+    let mut buf = [];
+    assert!(reader.read_exact(&mut buf).is_ok());
+    let mut buf = [8];
+    assert!(reader.read_exact(&mut buf).is_ok());
+    assert_eq!(buf[0], 0);
+    assert_eq!(reader.len(), 7);
+    let mut buf = [0, 0, 0, 0, 0, 0, 0];
+    assert!(reader.read_exact(&mut buf).is_ok());
+    assert_eq!(buf, [1, 2, 3, 4, 5, 6, 7]);
+    assert_eq!(reader.len(), 0);
+    let mut buf = [0];
+    assert!(reader.read_exact(&mut buf).is_err());
+}
+
+#[test]
+fn test_buf_reader() {
+    let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+    let mut reader = Cursor::new(&in_buf[..]);
+    let mut buf = [];
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    assert_eq!(reader.position(), 0);
+    let mut buf = [0];
+    assert_eq!(reader.read(&mut buf).unwrap(), 1);
+    assert_eq!(reader.position(), 1);
+    let b: &[_] = &[0];
+    assert_eq!(buf, b);
+    let mut buf = [0; 4];
+    assert_eq!(reader.read(&mut buf).unwrap(), 4);
+    assert_eq!(reader.position(), 5);
+    let b: &[_] = &[1, 2, 3, 4];
+    assert_eq!(buf, b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 3);
+    let b: &[_] = &[5, 6, 7];
+    assert_eq!(&buf[..3], b);
+    assert_eq!(reader.read(&mut buf).unwrap(), 0);
+}
+
+#[test]
+fn seek_past_end() {
+    let buf = [0xff];
+    let mut r = Cursor::new(&buf[..]);
+    assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+    assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+    let mut r = Cursor::new(vec![10]);
+    assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+    assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+    let mut buf = [0];
+    let mut r = Cursor::new(&mut buf[..]);
+    assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+    assert_eq!(r.write(&[3]).unwrap(), 0);
+
+    let mut r = Cursor::new(vec![10].into_boxed_slice());
+    assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+    assert_eq!(r.write(&[3]).unwrap(), 0);
+}
+
+#[test]
+fn seek_past_i64() {
+    let buf = [0xff];
+    let mut r = Cursor::new(&buf[..]);
+    assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+    assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+    assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+    assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+    assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+    assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+
+    let mut r = Cursor::new(vec![10]);
+    assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+    assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+    assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+    assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+    assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+    assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+
+    let mut buf = [0];
+    let mut r = Cursor::new(&mut buf[..]);
+    assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+    assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+    assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+    assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+    assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+    assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+
+    let mut r = Cursor::new(vec![10].into_boxed_slice());
+    assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+    assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+    assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+    assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+    assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+    assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+}
+
+#[test]
+fn seek_before_0() {
+    let buf = [0xff];
+    let mut r = Cursor::new(&buf[..]);
+    assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+    let mut r = Cursor::new(vec![10]);
+    assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+    let mut buf = [0];
+    let mut r = Cursor::new(&mut buf[..]);
+    assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+    let mut r = Cursor::new(vec![10].into_boxed_slice());
+    assert!(r.seek(SeekFrom::End(-2)).is_err());
+}
+
+#[test]
+fn test_seekable_mem_writer() {
+    let mut writer = Cursor::new(Vec::<u8>::new());
+    assert_eq!(writer.position(), 0);
+    assert_eq!(writer.write(&[0]).unwrap(), 1);
+    assert_eq!(writer.position(), 1);
+    assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+    assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+    assert_eq!(writer.position(), 8);
+    let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+    assert_eq!(&writer.get_ref()[..], b);
+
+    assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+    assert_eq!(writer.position(), 0);
+    assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+    let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+    assert_eq!(&writer.get_ref()[..], b);
+
+    assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+    assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+    let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+    assert_eq!(&writer.get_ref()[..], b);
+
+    assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+    assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+    let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+    assert_eq!(&writer.get_ref()[..], b);
+
+    assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+    assert_eq!(writer.write(&[1]).unwrap(), 1);
+    let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+    assert_eq!(&writer.get_ref()[..], b);
+}
+
+#[test]
+fn vec_seek_past_end() {
+    let mut r = Cursor::new(Vec::new());
+    assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+    assert_eq!(r.write(&[3]).unwrap(), 1);
+}
+
+#[test]
+fn vec_seek_before_0() {
+    let mut r = Cursor::new(Vec::new());
+    assert!(r.seek(SeekFrom::End(-2)).is_err());
+}
+
+#[test]
+#[cfg(target_pointer_width = "32")]
+fn vec_seek_and_write_past_usize_max() {
+    let mut c = Cursor::new(Vec::new());
+    c.set_position(usize::MAX as u64 + 1);
+    assert!(c.write_all(&[1, 2, 3]).is_err());
+}
+
+#[test]
+fn test_partial_eq() {
+    assert_eq!(Cursor::new(Vec::<u8>::new()), Cursor::new(Vec::<u8>::new()));
+}
+
+#[test]
+fn test_eq() {
+    struct AssertEq<T: Eq>(pub T);
+
+    let _: AssertEq<Cursor<Vec<u8>>> = AssertEq(Cursor::new(Vec::new()));
+}