keep dirty pages based on temp file

weed/filesys/page_writer/chunked_file_writer_test.go

@@ -0,0 +1,60 @@
+package page_writer
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+)
+
+func TestChunkedFileWriter_toActualOffset(t *testing.T) {
+	cw := NewChunkedFileWriter("", 16)
+
+	writeToFile(cw, 50, 60)
+	writeToFile(cw, 60, 64)
+
+	writeToFile(cw, 32, 40)
+	writeToFile(cw, 42, 48)
+
+	writeToFile(cw, 48, 50)
+
+	assert.Equal(t, 1, cw.chunkUsages[0].size(), "fully covered")
+	assert.Equal(t, 2, cw.chunkUsages[1].size(), "2 intervals")
+
+}
+
+func writeToFile(cw *ChunkedFileWriter, startOffset int64, stopOffset int64) {
+
+	_, chunkUsage := cw.toActualWriteOffset(startOffset)
+
+	// skip doing actual writing
+
+	innerOffset := startOffset % cw.ChunkSize
+	chunkUsage.MarkWritten(innerOffset, innerOffset+stopOffset-startOffset)
+
+}
+
+func TestWriteChunkedFile(t *testing.T) {
+	x := NewChunkedFileWriter(os.TempDir(), 20)
+	defer x.Reset()
+	y := NewChunkedFileWriter(os.TempDir(), 12)
+	defer y.Reset()
+
+	batchSize := 4
+	buf := make([]byte, batchSize)
+	for i := 0; i < 256; i++ {
+		for x := 0; x < batchSize; x++ {
+			buf[x] = byte(i)
+		}
+		x.WriteAt(buf, int64(i*batchSize))
+		y.WriteAt(buf, int64((255-i)*batchSize))
+	}
+
+	a := make([]byte, 1)
+	b := make([]byte, 1)
+	for i := 0; i < 256*batchSize; i++ {
+		x.ReadDataAt(a, int64(i))
+		y.ReadDataAt(b, int64(256*batchSize-1-i))
+		assert.Equal(t, a[0], b[0], "same read")
+	}
+
+}