Add task1 in go

Author: Holger Lösken

src/go/t1/s1.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func Maskify(cc string) string {
+	var masked = make([]string, len(cc))
+	var splitted = strings.Split(cc, "")
+
+	for idx, item := range splitted {
+		// Exclude first and last four items
+		if idx == 0 || idx >= len(splitted) - 4 {
+			masked = append(masked, item)
+			continue
+		}
+
+		// Check if is numeric
+		_, err := strconv.Atoi(item)
+
+		if err != nil {
+			masked = append(masked, item)
+			continue
+		}
+
+		masked = append(masked, "#")
+	}
+
+	return strings.Join(masked, "")
+}
+
+func main()  {
+	cc := ""
+
+	if len(os.Args) > 1 {
+		cc = os.Args[1]
+	} else {
+		os.Exit(0)
+	}
+
+	// Do no mask if cc less than 6 or empty string
+	if len(cc) < 6 {
+		fmt.Println(cc)
+		os.Exit(0)
+	}
+
+	fmt.Printf(Maskify(cc))
+}

src/go/t1/s1_test.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestMaskify(t *testing.T) {
+	type test struct {
+		input string
+		want  string
+	}
+
+	tests := []test{
+		{input: "12345", want: "12345"},
+		{input: "1234-4567-8901", want: "1###-####-8901"},
+		{input: "123456789", want: "1####6789"},
+	}
+
+	for _, tc := range tests {
+		got := Maskify(tc.input)
+		if !reflect.DeepEqual(tc.want, got) {
+			t.Fatalf("expected: %v, got: %v", tc.want, got)
+		}
+	}
+}