diff --git a/whisper/whisperv5/filter_test.go b/whisper/whisperv5/filter_test.go
index 0b0b282a08..8c868c66a4 100644
--- a/whisper/whisperv5/filter_test.go
+++ b/whisper/whisperv5/filter_test.go
@@ -216,6 +216,14 @@ func TestInstallIdenticalFilters(t *testing.T) {
 		t.Fatalf("failed matching with the first filter")
 	}
 
+	if ! filter2.MatchEnvelope(env) {
+		t.Fatalf("failed matching with the first filter")
+	}
+
+	if ! filter1.MatchMessage(msg) {
+		t.Fatalf("failed matching with the second filter")
+	}
+
 	if ! filter2.MatchMessage(msg) {
 		t.Fatalf("failed matching with the second filter")
 	}
diff --git a/whisper/whisperv5/whisper_test.go b/whisper/whisperv5/whisper_test.go
index 9957412e85..f18752c8c5 100644
--- a/whisper/whisperv5/whisper_test.go
+++ b/whisper/whisperv5/whisper_test.go
@@ -704,7 +704,7 @@ func TestSymmetricSendCycle(t *testing.T) {
 	}
 
 	// check w.messages()
-	time.Sleep(100 * time.Millisecond)
+	time.Sleep(5 * time.Millisecond)
 	mail1 := filter1.Retrieve()
 	mail2 := filter2.Retrieve()
 	if len(mail2) == 0 {
@@ -777,7 +777,7 @@ func TestSymmetricSendWithoutAKey(t *testing.T) {
 	}
 
 	// check w.messages()
-	time.Sleep(100 * time.Millisecond)
+	time.Sleep(5 * time.Millisecond)
 	mail := filter.Retrieve()
 	if len(mail) == 0 {
 		t.Fatalf("did not receive message in spite of not setting a public key")
@@ -843,7 +843,7 @@ func TestSymmetricSendKeyMismatch(t *testing.T) {
 	}
 
 	// check w.messages()
-	time.Sleep(100 * time.Millisecond)
+	time.Sleep(5 * time.Millisecond)
 	mail := filter.Retrieve()
 	if len(mail) > 0 {
 		t.Fatalf("received a message when keys weren't matching")