lib/bucket: implement bucket.Join a simplified path.Join

lib/bucket/bucket.go

@@ -29,6 +29,23 @@ func Split(absPath string) (bucket, bucketPath string) {
 	return absPath[:slash], absPath[slash+1:]
 }
 
+// Join joins any number of path elements into a single path, adding a
+// separating slash if necessary. Empty elements are ignored.
+//
+// Unlike path.Join this does not run path.Clean on the elements so a
+// path called "." will be preserved.
+func Join(elem ...string) (out string) {
+	for _, e := range elem {
+		if e != "" {
+			if out != "" {
+				out += "/"
+			}
+			out += e
+		}
+	}
+	return out
+}
+
 // 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 +25,25 @@ func TestSplit(t *testing.T) {
 	}
 }
 
+func TestJoin(t *testing.T) {
+	for _, test := range []struct {
+		in   []string
+		want string
+	}{
+		{in: []string{}, want: ""},
+		{in: []string{""}, want: ""},
+		{in: []string{"", ""}, want: ""},
+		{in: []string{"", "b"}, want: "b"},
+		{in: []string{"a", ""}, want: "a"},
+		{in: []string{"a", "b"}, want: "a/b"},
+		{in: []string{"a/b/c", "..", "."}, want: "a/b/c/../."},
+	} {
+		got := Join(test.in...)
+		what := fmt.Sprintf("Join(%q)", test.in)
+		assert.Equal(t, test.want, got, what)
+	}
+}
+
 func TestCache(t *testing.T) {
 	c := NewCache()
 	errBoom := errors.New("boom")