whisper: fix empty topic (#15811)

* whisper: fix empty topic

* whisper: add check to matchSingleTopic

* whisper: add tests

* whisper: fix gosimple

* whisper: added lastTopicByte const

1 files changed, 39 insertions, 5 deletions

diff --git a/whisper/whisperv6/filter_test.go b/whisper/whisperv6/filter_test.go
index e2877b233..9c7fdad95 100644
--- a/whisper/whisperv6/filter_test.go
+++ b/whisper/whisperv6/filter_test.go
@@ -800,6 +800,7 @@ func TestWatchers(t *testing.T) {
 func TestVariableTopics(t *testing.T) {
 	InitSingleTest()
 
+	const lastTopicByte = 3
 	var match bool
 	params, err := generateMessageParams()
 	if err != nil {
@@ -820,19 +821,52 @@ func TestVariableTopics(t *testing.T) {
 	}
 
 	for i := 0; i < 4; i++ {
-		arr := make([]byte, i+1, 4)
-		copy(arr, env.Topic[:i+1])
-
-		f.Topics[4] = arr
+		env.Topic = BytesToTopic(f.Topics[i])
 		match = f.MatchEnvelope(env)
 		if !match {
 			t.Fatalf("failed MatchEnvelope symmetric with seed %d, step %d.", seed, i)
 		}
 
-		f.Topics[4][i]++
+		f.Topics[i][lastTopicByte]++
 		match = f.MatchEnvelope(env)
 		if match {
 			t.Fatalf("MatchEnvelope symmetric with seed %d, step %d: false positive.", seed, i)
 		}
 	}
 }
+
+func TestMatchSingleTopic_ReturnTrue(t *testing.T) {
+	bt := []byte("test")
+	topic := BytesToTopic(bt)
+
+	if !matchSingleTopic(topic, bt) {
+		t.FailNow()
+	}
+}
+
+func TestMatchSingleTopic_WithTail_ReturnTrue(t *testing.T) {
+	bt := []byte("test with tail")
+	topic := BytesToTopic([]byte("test"))
+
+	if !matchSingleTopic(topic, bt) {
+		t.FailNow()
+	}
+}
+
+func TestMatchSingleTopic_NotEquals_ReturnFalse(t *testing.T) {
+	bt := []byte("tes")
+	topic := BytesToTopic(bt)
+
+	if matchSingleTopic(topic, bt) {
+		t.FailNow()
+	}
+}
+
+func TestMatchSingleTopic_InsufficientLength_ReturnFalse(t *testing.T) {
+	bt := []byte("test")
+	topic := BytesToTopic([]byte("not_equal"))
+
+	if matchSingleTopic(topic, bt) {
+		t.FailNow()
+	}
+}