Table.SortBy can't handle empty cells

[Skeeve]

Describe the bug

The last column of your test table has no values for two rows. Sorting that column fails.

To Reproduce

Put this into table_test.go:

func TestTable_MoreSort(t *testing.T) {
	table := Table{}
	table.AppendRows(testRows)
	table.AppendHeader(testHeader)
	table.SetStyle(styleTest)
	expectedOut := `(-----^------------^-----------^--------^-----------------------------)
[<#  >|<FIRST NAME>|<LAST NAME>|<SALARY>|<                           >]
{-----+------------+-----------+--------+-----------------------------}
[<20 >|<Jon       >|<Snow     >|<  2000>|<You know nothing, Jon Snow!>]
[<300>|<Tyrion    >|<Lannister>|<  5000>|<                           >]
[<1  >|<Arya      >|<Stark    >|<  3000>|<                           >]
\-----v------------v-----------v--------v-----------------------------/`
	table.SortBy([]SortBy{{Number: 5, Mode: Dsc}, {Name: "Last Name", Mode: Asc}})
	assert.Equal(t, expectedOut, table.Render())
}

Expected behavior

Expactation is that empty cells are sorted according to their string, representation.

The expected output is given in the code.

Screenshots

Actual output:

(-----^------------^-----------^--------^-----------------------------)
[<  #>|<FIRST NAME>|<LAST NAME>|<SALARY>|<                           >]
{-----+------------+-----------+--------+-----------------------------}
[<300>|<Tyrion    >|<Lannister>|<  5000>|<                           >]
[< 20>|<Jon       >|<Snow     >|<  2000>|<You know nothing, Jon Snow!>]
[<  1>|<Arya      >|<Stark    >|<  3000>|<                           >]
\-----v------------v-----------v--------v-----------------------------/

As you see: Column 5 isn't properly sorted.

Software (please complete the following information):

• OS: Mac OS - But I'm using a dockerized go
• GoLang Version dockerized golang:latest

[jedib0t]

Release with fix: https://github.com/jedib0t/go-pretty/releases/tag/v6.5.5