added unit test for descending order, fixed deduplication bug

TODO.md

@@ -1,7 +1,5 @@
 ## Fixes to be implemented
 
-- add unit test for descending sort order
-
 ## Features to be implemented
 
 - sorting by: numerical, time, duration, string(default)

lib/helpers.go

@@ -23,6 +23,7 @@ import (
 	"github.com/gookit/color"
 	"os"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 )
@@ -71,8 +72,10 @@ func PrepareColumns(data *Tabdata) error {
 			}
 		}
 
-		// deduplicate
+		// deduplicate: put all values into a map (value gets map key)
-		imap := make(map[int]int)
+		// thereby  removing duplicates,  extract keys into  new slice
+		// and sort it
+		imap := make(map[int]int, len(UseColumns))
 		for _, i := range UseColumns {
 			imap[i] = 0
 		}
@@ -80,6 +83,7 @@ func PrepareColumns(data *Tabdata) error {
 		for k := range imap {
 			UseColumns = append(UseColumns, k)
 		}
+		sort.Ints(UseColumns)
 	}
 	return nil
 }

lib/printer_test.go

@@ -153,11 +153,13 @@ func TestSortPrinter(t *testing.T) {
 	var tests = []struct {
 		data   Tabdata
 		sortby int
+		desc   bool
 		expect string
 	}{
 		{
 			data:   startdata,
 			sortby: 1,
+			desc:   false,
 			expect: `ONE(1)	TWO(2)	THREE(3) 
 abc   	345   	b1      	
 bcd   	234   	a2      	
@@ -167,6 +169,7 @@ cde   	123   	c3`,
 		{
 			data:   startdata,
 			sortby: 2,
+			desc:   false,
 			expect: `ONE(1)	TWO(2)	THREE(3) 
 cde   	123   	c3      	
 bcd   	234   	a2      	
@@ -176,11 +179,21 @@ abc   	345   	b1`,
 		{
 			data:   startdata,
 			sortby: 3,
+			desc:   false,
 			expect: `ONE(1)	TWO(2)	THREE(3) 
 bcd   	234   	a2      	
 abc   	345   	b1      	
 cde   	123   	c3`,
 		},
+		{
+			data:   startdata,
+			sortby: 1,
+			desc:   true,
+			expect: `ONE(1)	TWO(2)	THREE(3) 
+cde   	123   	c3      	
+bcd   	234   	a2      	
+abc   	345   	b1`,
+		},
 	}
 
 	NoColor = true
@@ -188,9 +201,10 @@ cde   	123   	c3`,
 	origStdout, reader := stdout2pipe(t)
 
 	for _, tt := range tests {
-		testname := fmt.Sprintf("print-sorted-table-%d", tt.sortby)
+		testname := fmt.Sprintf("print-sorted-table-by-%d-desc-%t", tt.sortby, tt.desc)
 		t.Run(testname, func(t *testing.T) {
 			SortByColumn = tt.sortby
+			SortDescending = tt.desc
 
 			printData(&tt.data)