Function TestAsyncBufferReadAsync

asyncbuffer/buffer_test.go:342–384

TestAsyncBufferReadAsync tests reading from AsyncBuffer using readAt method with full = false

(t *testing.T)

// TestAsyncBufferReadAsync tests reading from AsyncBuffer using readAt method
// with full = false
func TestAsyncBufferReadAsync(t *testing.T) {
	// Let's use source buffer which is 4.5 chunks long
	source, bytesReader := generateSourceData(t, asyncbuffer.ChunkSize*3)
	br := newBlockingReader(bytesReader)
	ab := asyncbuffer.New(br, -1)
	defer ab.Close()

	// flush the first chunk to allow reading
	br.flushNextChunk()

	// Let's try to read first two chunks, however,
	// we know that only the first chunk is available
	target := make([]byte, asyncbuffer.ChunkSize*2)
	n, err := ab.ReadAt(target, 0)
	require.NoError(t, err)
	assert.Equal(t, asyncbuffer.ChunkSize, n)
	assert.Equal(t, target[:asyncbuffer.ChunkSize], source[:asyncbuffer.ChunkSize])

	br.flushNextChunk()                   // unlock reader to allow read second chunk
	ab.WaitFor(asyncbuffer.ChunkSize + 1) // wait for the second chunk to be available

	target = make([]byte, asyncbuffer.ChunkSize*2)
	n, err = ab.ReadAt(target, 0)
	require.NoError(t, err)
	assert.Equal(t, asyncbuffer.ChunkSize*2, n)
	assert.Equal(t, target, source[:asyncbuffer.ChunkSize*2])

	br.flush() // Flush the rest of the data
	ab.Wait()

	// Try to read near end of the stream, EOF
	target = make([]byte, asyncbuffer.ChunkSize)
	n, err = ab.ReadAt(target, asyncbuffer.ChunkSize*3-1)
	require.NoError(t, err)
	assert.Equal(t, 1, n)
	assert.Equal(t, target[0], source[asyncbuffer.ChunkSize*3-1])

	// Try to read beyond the end of the stream == eof
	target = make([]byte, asyncbuffer.ChunkSize)
	n, err = ab.ReadAt(target, asyncbuffer.ChunkSize*3)
	require.ErrorIs(t, io.EOF, err)
	assert.Equal(t, 0, n)
}

// TestAsyncBufferWithDataLenAndExactReaderSize tests that AsyncBuffer doesn't
// return an error when the expected data length is set and matches the reader size