tlsopts: fix helper (#1515)

pkg/peertls/tlsopts/options.go

@@ -174,11 +174,11 @@ func (vf *VerificationFuncs) ServerAdd(verificationFuncs ...peertls.PeerCertVeri
 }
 
 func removeNils(verificationFuncs []peertls.PeerCertVerificationFunc) []peertls.PeerCertVerificationFunc {
-	for i, f := range verificationFuncs {
-		if f == nil {
-			copy(verificationFuncs[i:], verificationFuncs[i+1:])
-			verificationFuncs = verificationFuncs[:len(verificationFuncs)-1]
+	result := verificationFuncs[:0]
+	for _, f := range verificationFuncs {
+		if f != nil {
+			result = append(result, f)
 		}
 	}
-	return verificationFuncs
+	return result
 }

pkg/peertls/tlsopts/options_internal_test.go

@@ -0,0 +1,26 @@
+// Copyright (C) 2019 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+package tlsopts
+
+import (
+	"crypto/x509"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"storj.io/storj/pkg/peertls"
+)
+
+func TestRemoveNils(t *testing.T) {
+	e1 := fmt.Errorf("error 1")
+	f1 := peertls.PeerCertVerificationFunc(func([][]byte, [][]*x509.Certificate) error { return e1 })
+	e2 := fmt.Errorf("error 2")
+	f2 := peertls.PeerCertVerificationFunc(func([][]byte, [][]*x509.Certificate) error { return e2 })
+
+	l := removeNils([]peertls.PeerCertVerificationFunc{f1, nil, nil, f2})
+	require.Equal(t, len(l), 2)
+	require.Equal(t, l[0](nil, nil), e1)
+	require.Equal(t, l[1](nil, nil), e2)
+}