diff --git a/metropolis/pkg/msguid/msguid_test.go b/metropolis/pkg/msguid/msguid_test.go
new file mode 100644
index 0000000..b8cdfea
--- /dev/null
+++ b/metropolis/pkg/msguid/msguid_test.go
@@ -0,0 +1,40 @@
+package msguid
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/uuid"
+)
+
+func TestRoundTrip(t *testing.T) {
+	cases := []struct {
+		name     string
+		uuid     string
+		expected [16]byte
+	}{
+		{
+			"WikipediaExample1",
+			"00112233-4455-6677-8899-AABBCCDDEEFF",
+			[16]byte{
+				0x33, 0x22, 0x11, 0x00, 0x55, 0x44, 0x77, 0x66,
+				0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF,
+			},
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			origUUID := uuid.MustParse(c.uuid)
+			got := From(origUUID)
+			diff := cmp.Diff(c.expected, got)
+			if diff != "" {
+				t.Fatalf("To(%q) returned unexpected result: %v", origUUID, diff)
+			}
+			back := To(got)
+			diff2 := cmp.Diff(origUUID, back)
+			if diff2 != "" {
+				t.Errorf("From(To(%q)) did not return original value: %v", origUUID, diff2)
+			}
+		})
+	}
+}