Apply changes suggested by staticcheck

cell.go

@@ -509,22 +509,6 @@ func (c *Cell) GetNumberFormat() string {
 	return c.NumFmt
 }
 
-func (c *Cell) formatToFloat(format string) (string, error) {
-	f, err := strconv.ParseFloat(c.Value, 64)
-	if err != nil {
-		return c.Value, err
-	}
-	return fmt.Sprintf(format, f), nil
-}
-
-func (c *Cell) formatToInt(format string) (string, error) {
-	f, err := strconv.ParseFloat(c.Value, 64)
-	if err != nil {
-		return c.Value, err
-	}
-	return fmt.Sprintf(format, int(f)), nil
-}
-
 // getNumberFormat will update the parsedNumFmt struct if it has become out of date, since a cell's NumFmt string is a
 // public field that could be edited by clients.
 func (c *Cell) getNumberFormat() *parsedNumberFormat {

cell_test.go

@@ -629,7 +629,7 @@ func TestCell(t *testing.T) {
 		smallDate := time.Date(1899, 12, 30, 0, 0, 0, 1000, time.UTC)
 		smallExcelTime := TimeToExcelTime(smallDate, false)
 
-		c.Assert(true, qt.Equals, 0.0 != smallExcelTime)
+		c.Assert(0.0, qt.Not(qt.Equals), smallExcelTime)
 		roundTrippedDate := TimeFromExcelTime(smallExcelTime, false)
 		c.Assert(roundTrippedDate, qt.Equals, smallDate)
 	})
@@ -933,16 +933,6 @@ func (fvc *formattedValueChecker) Equals(cell Cell, expected string) {
 	fvc.c.Assert(val, qt.Equals, expected)
 }
 
-func cellsFormattedValueEquals(t *testing.T, cell *Cell, expected string) {
-	val, err := cell.FormattedValue()
-	if err != nil {
-		t.Error(err)
-	}
-	if val != expected {
-		t.Errorf("Expected cell.FormattedValue() to be %v, got %v", expected, val)
-	}
-}
-
 func TestCellMerge(t *testing.T) {
 	c := qt.New(t)
 	csRunO(c, "MergeAndSave", func(c *qt.C, option FileOption) {
@@ -956,7 +946,7 @@ func TestCellMerge(t *testing.T) {
 		cell := row.AddCell()
 		cell.Value = "test"
 		cell.Merge(1, 0)
-		path := filepath.Join(c.Mkdir(), "merged.xlsx")
+		path := filepath.Join(t.TempDir(), "merged.xlsx")
 		err = f.Save(path)
 		c.Assert(err, qt.Equals, nil)
 	})