}{
		{1, 0},
		{2, 1},
		{4, 2},
		{5, 3},
		{7, 4},
		// Insert part.
		{3, 2},
		// Replace existing part.
		{4, 3},
		// Missing part.
		{6, -1},
	}

	// Setup.
	fi := newFileInfo("test-object", 8, 8)
	fi.Erasure.Index = 1
	if !fi.IsValid() {
		t.Fatalf("unable to get xl meta")
	}

	// Test them.
	for _, testCase := range testCases {
		if testCase.expectedIndex > -1 {