}

// Errors specifically generated by calculatePartSizeFromIdx function.
var (
	errPartSizeZero  = errors.New("Part size cannot be zero")
	errPartSizeIndex = errors.New("Part index cannot be smaller than 1")
)

// calculatePartSizeFromIdx calculates the part size according to input index.
// returns error if totalSize is -1, partSize is 0, partIndex is 0.

		{5 * humanize.MiByte, 2 * humanize.MiByte, 3, 1 * humanize.MiByte},
		{5 * humanize.MiByte, 2 * humanize.MiByte, 4, 0},
	}

	for i, testCase := range testCases {
		s, err := calculatePartSizeFromIdx(GlobalContext, testCase.totalSize, testCase.partSize, testCase.partIndex)
		if err != nil {
			t.Errorf("Test %d: Expected to pass but failed. %s", i+1, err)
		}
		if err == nil && s != testCase.expectedSize {