add tests for prefix+marker case

Author: ahouene

backends/s3/s3_test.go

@@ -110,7 +110,14 @@ func TestBackend_globalprefix(t *testing.T) {
 	b.opt.GlobalPrefix = "v5/"
 
 	tester.DoBackendTests(t, b)
-	assert.Len(t, b.lastMarker, 0)
+	assert.Empty(t, b.lastMarker)
+
+	b = getBackend(ctx, t)
+	b.opt.GlobalPrefix = "v6/"
+	b.opt.UseUpdateMarker = true
+
+	tester.DoBackendTests(t, b)
+	assert.NotEmpty(t, b.lastMarker)
 }
 
 func TestBackend_recursive(t *testing.T) {

tester/tester.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/PowerDNS/simpleblob"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // DoBackendTests tests a backend for conformance
@@ -41,6 +42,7 @@ func DoBackendTests(t *testing.T, b simpleblob.Interface) {
 	ls, err = b.List(ctx, "foo-")
 	assert.NoError(t, err)
 	assert.Equal(t, ls.Names(), []string{"foo-1"})
+	require.NotEmpty(t, ls)
 	assert.Equal(t, ls[0].Size, int64(3))
 	ls, err = b.List(ctx, "bar-")
 	assert.NoError(t, err)