resolved the gosec issue failing unit tests (redhat-developer#3358)

* resolved the gosec issue failing unit tests

* resolved typo in the comment

* DRYed the code

pkg/util/util.go

@@ -4,10 +4,11 @@ import (
 	"archive/zip"
 	"bufio"
 	"context"
+	"crypto/rand"
 	"fmt"
 	"io"
 	"io/ioutil"
-	"math/rand"
+	"math/big"
 	"net"
 	"net/http"
 	"net/url"
@@ -81,10 +82,13 @@ func ConvertLabelsToSelector(labels map[string]string) string {
 // GenerateRandomString generates a random string of lower case characters of
 // the given size
 func GenerateRandomString(n int) string {
-	rand.Seed(time.Now().UnixNano())
 	b := make([]rune, n)
+
 	for i := range b {
-		b[i] = letterRunes[rand.Intn(len(letterRunes))]
+		// this error is ignored because it fails only when the 2nd arg of Int() is less then 0
+		// which wont happen
+		n, _ := rand.Int(rand.Reader, big.NewInt(int64(len(letterRunes))))
+		b[i] = letterRunes[n.Int64()]
 	}
 	return string(b)
 }

tests/helper/helper_generic.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"math/rand"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -14,20 +13,12 @@ import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/onsi/gomega/gexec"
+	"github.com/openshift/odo/pkg/util"
 )
 
-func init() {
-	rand.Seed(time.Now().UTC().UnixNano())
-}
-
 // RandString returns a random string of given length
 func RandString(n int) string {
-	const letterBytes = "abcdefghijklmnopqrstuvwxyz"
-	b := make([]byte, n)
-	for i := range b {
-		b[i] = letterBytes[rand.Intn(len(letterBytes))]
-	}
-	return string(b)
+	return util.GenerateRandomString(n)
 }
 
 // WaitForCmdOut runs a command until it gets