add test to ensure that extension statuses for missing stems are fact…

…ored

See crate-crypto/rust-verkle#50 for context

proof_test.go

@@ -415,7 +415,7 @@ func TestProofOfAbsenceEdgeCase(t *testing.T) {
 	}
 }
 
-func TestProofOfAbsenceOtherMultiple(t *testing.T) {
+func TestProofOfAbsenceOtherMultipleLeaves(t *testing.T) {
 	// Create a stem that isn't the one that will be proven,
 	// but does look the same for most of its length.
 	root := New()
@@ -435,3 +435,26 @@ func TestProofOfAbsenceOtherMultiple(t *testing.T) {
 		t.Fatalf("invalid number of proof-of-absence stems: %d", len(proof.PoaStems))
 	}
 }
+
+func TestProofOfAbsenceNoneMultipleStems(t *testing.T) {
+	root := New()
+	key, _ := hex.DecodeString("0403030303030303030303030303030303030303030303030303030303030000")
+	root.Insert(key, testValue, nil)
+	root.ComputeCommitment()
+
+	ret1, _ := hex.DecodeString("0303030303030303030303030303030303030303030303030303030303030300")
+	ret2, _ := hex.DecodeString("0303030303030303030303030303030303030303030303030303030303030200")
+	proof, cs, zis, yis := MakeVerkleMultiProof(root, [][]byte{ret1, ret2}, map[string][]byte{string(ret1): nil, string(ret2): nil})
+	cfg, _ := GetConfig()
+	if !VerifyVerkleProof(proof, cs, zis, yis, cfg) {
+		t.Fatal("could not verify proof")
+	}
+
+	if len(proof.PoaStems) != 0 {
+		t.Fatalf("invalid number of proof-of-absence stems: %d", len(proof.PoaStems))
+	}
+
+	if len(proof.ExtStatus) != 1 {
+		t.Fatalf("invalid number of none extension statuses: %d ≠ 1", len(proof.ExtStatus))
+	}
+}