Add test for snapshot.Stats

Also, set directory mode and default permissions in mockfs.NewDirectory

internal/mockfs/mockfs.go

@@ -227,6 +227,7 @@ func NewDirectory() *Directory {
 	return &Directory{
 		entry: entry{
 			name: "<root>",
+			mode: 0777 | os.ModeDir,
 		},
 	}
 }

snapshot/stats_test.go

@@ -0,0 +1,40 @@
+package snapshot_test
+
+import (
+	"testing"
+
+	"github.com/kopia/kopia/fs"
+	"github.com/kopia/kopia/internal/mockfs"
+	"github.com/kopia/kopia/snapshot"
+)
+
+func TestStats(t *testing.T) {
+	d := mockfs.NewDirectory()
+	f := d.AddFile("foo", []byte{'b', 'a', 'r', 'b', 'a', 'z'}, 0)
+	tcs := []struct {
+		entry fs.Entry
+		want  snapshot.Stats
+	}{
+		{
+			entry: d,
+			want: snapshot.Stats{
+				ExcludedDirCount: 1,
+			},
+		},
+		{
+			entry: f,
+			want: snapshot.Stats{
+				ExcludedFileCount:     1,
+				ExcludedTotalFileSize: f.Size(),
+			},
+		},
+	}
+
+	for _, tc := range tcs {
+		got := snapshot.Stats{}
+		got.AddExcluded(tc.entry)
+		if got != tc.want {
+			t.Errorf("Stats do not match, got: %#v, want %#v", got, tc.want)
+		}
+	}
+}