🚧 Add Defrag function

defrag_test.go

@@ -0,0 +1,19 @@
+package defrag
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDefrag(t *testing.T) {
+	for _, testcase := range sampleTests() {
+		t.Run(testcase.name, func(sub *testing.T) {
+			blocks := make([]byte, len(testcase.blocks))
+			copy(blocks, testcase.blocks)
+			err := Defrag(blocks)
+			require.NoError(sub, err)
+			require.Equal(sub, testcase.defragged, blocks)
+		})
+	}
+}