hashing: move to repository package

internal/repository/hashing/reader_test.go

@@ -0,0 +1,72 @@
+package hashing
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/sha256"
+	"io"
+	"testing"
+)
+
+func TestReader(t *testing.T) {
+	tests := []int{5, 23, 2<<18 + 23, 1 << 20}
+
+	for _, size := range tests {
+		data := make([]byte, size)
+		_, err := io.ReadFull(rand.Reader, data)
+		if err != nil {
+			t.Fatalf("ReadFull: %v", err)
+		}
+
+		expectedHash := sha256.Sum256(data)
+
+		rd := NewReader(bytes.NewReader(data), sha256.New())
+		n, err := io.Copy(io.Discard, rd)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if n != int64(size) {
+			t.Errorf("Reader: invalid number of bytes written: got %d, expected %d",
+				n, size)
+		}
+
+		resultingHash := rd.Sum(nil)
+
+		if !bytes.Equal(expectedHash[:], resultingHash) {
+			t.Errorf("Reader: hashes do not match: expected %02x, got %02x",
+				expectedHash, resultingHash)
+		}
+	}
+}
+
+func BenchmarkReader(b *testing.B) {
+	buf := make([]byte, 1<<22)
+	_, err := io.ReadFull(rand.Reader, buf)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	expectedHash := sha256.Sum256(buf)
+
+	b.SetBytes(int64(len(buf)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		rd := NewReader(bytes.NewReader(buf), sha256.New())
+		n, err := io.Copy(io.Discard, rd)
+		if err != nil {
+			b.Fatal(err)
+		}
+
+		if n != int64(len(buf)) {
+			b.Errorf("Reader: invalid number of bytes written: got %d, expected %d",
+				n, len(buf))
+		}
+
+		resultingHash := rd.Sum(nil)
+		if !bytes.Equal(expectedHash[:], resultingHash) {
+			b.Errorf("Reader: hashes do not match: expected %02x, got %02x",
+				expectedHash, resultingHash)
+		}
+	}
+}