Add tests for positioned reads (#212)

Author: Kimahriman

rust/src/file.rs

@@ -88,8 +88,7 @@ impl FileReader {
             let offset = self.position;
             self.position = usize::min(self.position + buf.len(), self.file_length());
             let read_bytes = self.position - offset;
-            let buf = &mut buf[..read_bytes];
-            self.read_range_buf(buf, offset).await?;
+            self.read_range_buf(&mut buf[..read_bytes], offset).await?;
             Ok(read_bytes)
         }
     }
@@ -99,7 +98,7 @@ impl FileReader {
     ///
     /// Panics if the requested range is outside of the file
     pub async fn read_range(&self, offset: usize, len: usize) -> Result<Bytes> {
-        let mut stream = self.read_range_stream(offset, len).boxed();
+        let mut stream = self.read_range_stream(offset, len);
         let mut buf = BytesMut::with_capacity(len);
         while let Some(bytes) = stream.next().await.transpose()? {
             buf.put(bytes);
@@ -111,7 +110,7 @@ impl FileReader {
     ///
     /// Panics if the requested range is outside of the file
     pub async fn read_range_buf(&self, mut buf: &mut [u8], offset: usize) -> Result<()> {
-        let mut stream = self.read_range_stream(offset, buf.len()).boxed();
+        let mut stream = self.read_range_stream(offset, buf.len());
         while let Some(bytes) = stream.next().await.transpose()? {
             buf.put(bytes);
         }

rust/tests/test_read.rs

@@ -4,7 +4,7 @@ mod common;
 #[cfg(feature = "integration-test")]
 mod test {
     use crate::common::TEST_FILE_INTS;
-    use bytes::Buf;
+    use bytes::{Buf, BytesMut};
     use hdfs_native::{
         minidfs::{DfsFeatures, MiniDfs},
         Client, Result, WriteOptions,
@@ -60,7 +60,7 @@ mod test {
         file.close().await?;
 
         // Read the whole file
-        let reader = client.read("/testfile").await?;
+        let mut reader = client.read("/testfile").await?;
         let mut buf = reader.read_range(0, TEST_FILE_INTS * 4).await?;
         for i in 0..TEST_FILE_INTS as i32 {
             assert_eq!(buf.get_i32(), i);
@@ -82,6 +82,26 @@ mod test {
             offset += 1024 * 1024;
         }
 
+        // Positioned reads
+        let mut buf = reader.read(reader.file_length()).await?;
+        for i in 0..TEST_FILE_INTS as i32 {
+            assert_eq!(buf.get_i32(), i);
+        }
+
+        reader.seek(0);
+
+        let mut buf = BytesMut::zeroed(reader.file_length());
+        assert_eq!(reader.read_buf(&mut buf).await?, reader.file_length());
+        for i in 0..TEST_FILE_INTS as i32 {
+            assert_eq!(buf.get_i32(), i);
+        }
+
+        // Trying to read again should return nothing
+        assert!(reader.read(1).await?.is_empty());
+
+        // Same with reading into a provided buffer
+        assert_eq!(reader.read_buf(&mut [0u8]).await?, 0);
+
         Ok(())
     }
 }