bucket: add Join function for a simplified path.Join

lib/bucket/bucket.go

@@ -29,6 +29,19 @@ func Split(absPath string) (bucket, bucketPath string) {
 	return absPath[:slash], absPath[slash+1:]
 }
 
+// Join path1 and path2
+//
+// Like path.Join but does not clean the path - useful to preserve trailing /
+func Join(path1, path2 string) string {
+	if path1 == "" {
+		return path2
+	}
+	if path2 == "" {
+		return path1
+	}
+	return strings.TrimSuffix(path1, "/") + "/" + strings.TrimPrefix(path2, "/")
+}
+
 // Cache stores whether buckets are available and their IDs
 type Cache struct {
 	mu       sync.Mutex      // mutex to protect created and deleted

lib/bucket/bucket_test.go

@@ -2,6 +2,7 @@ package bucket
 
 import (
 	"errors"
+	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -24,6 +25,26 @@ func TestSplit(t *testing.T) {
 	}
 }
 
+func TestJoin(t *testing.T) {
+	for _, test := range []struct {
+		in1, in2 string
+		want     string
+	}{
+		{in1: "", in2: "", want: ""},
+		{in1: "in1", in2: "", want: "in1"},
+		{in1: "", in2: "in2", want: "in2"},
+		{in1: "in1", in2: "in2", want: "in1/in2"},
+		{in1: "in1/", in2: "in2", want: "in1/in2"},
+		{in1: "in1", in2: "/in2", want: "in1/in2"},
+		{in1: "in1", in2: "in2/", want: "in1/in2/"},
+		{in1: "/in1", in2: "/in2", want: "/in1/in2"},
+		{in1: "/in1", in2: "../in2", want: "/in1/../in2"},
+	} {
+		got := Join(test.in1, test.in2)
+		assert.Equal(t, test.want, got, fmt.Sprintf("in1=%q, in2=%q", test.in1, test.in2))
+	}
+}
+
 func TestCache(t *testing.T) {
 	c := NewCache()
 	errBoom := errors.New("boom")