diff --git a/peer_gater.go b/peer_gater.go
index 231b950..df86dad 100644
--- a/peer_gater.go
+++ b/peer_gater.go
@@ -62,7 +62,11 @@ func WithPeerGater(threshold, decay float64) Option {
 }
 
 func newPeerGater(ctx context.Context, threshold, decay float64) *peerGater {
-	pg := &peerGater{threshold: threshold, decay: decay}
+	pg := &peerGater{
+		threshold: threshold,
+		decay:     decay,
+		stats:     make(map[peer.ID]*peerGaterStats),
+	}
 	go pg.background(ctx)
 	return pg
 }
diff --git a/peer_gater_test.go b/peer_gater_test.go
new file mode 100644
index 0000000..488a216
--- /dev/null
+++ b/peer_gater_test.go
@@ -0,0 +1,88 @@
+package pubsub
+
+import (
+	"testing"
+	"time"
+
+	"github.com/libp2p/go-libp2p-core/peer"
+)
+
+func TestPeerGater(t *testing.T) {
+	pg := &peerGater{threshold: 0.1, decay: .9, stats: make(map[peer.ID]*peerGaterStats)}
+
+	peerA := peer.ID("A")
+	pg.AddPeer(peerA, "")
+
+	status := pg.AcceptFrom(peerA)
+	if status != AcceptAll {
+		t.Fatal("expected AcceptAll")
+	}
+
+	msg := &Message{ReceivedFrom: peerA}
+
+	pg.ValidateMessage(msg)
+	status = pg.AcceptFrom(peerA)
+	if status != AcceptAll {
+		t.Fatal("expected AcceptAll")
+	}
+
+	pg.RejectMessage(msg, rejectValidationQueueFull)
+	status = pg.AcceptFrom(peerA)
+	if status != AcceptAll {
+		t.Fatal("expected AcceptAll")
+	}
+
+	pg.RejectMessage(msg, rejectValidationThrottled)
+	status = pg.AcceptFrom(peerA)
+	if status != AcceptAll {
+		t.Fatal("expected AcceptAll")
+	}
+
+	pg.RejectMessage(msg, rejectValidationIgnored)
+	status = pg.AcceptFrom(peerA)
+	if status != AcceptControl {
+		t.Fatal("expected AcceptControl")
+	}
+
+	pg.RejectMessage(msg, rejectValidationFailed)
+	status = pg.AcceptFrom(peerA)
+	if status != AcceptControl {
+		t.Fatal("expected AcceptControl")
+	}
+
+	for i := 0; i < 100; i++ {
+		pg.DeliverMessage(msg)
+	}
+
+	accepted := false
+	for i := 0; !accepted && i < 1000; i++ {
+		status = pg.AcceptFrom(peerA)
+		if status == AcceptAll {
+			accepted = true
+		}
+	}
+	if !accepted {
+		t.Fatal("expected to accept at least once")
+	}
+
+	for i := 0; i < 100; i++ {
+		pg.decayStats()
+	}
+
+	status = pg.AcceptFrom(peerA)
+	if status != AcceptAll {
+		t.Fatal("expected AcceptAll")
+	}
+
+	pg.RemovePeer(peerA)
+	pg.stats[peerA].expire = time.Now()
+
+	time.Sleep(time.Millisecond)
+
+	pg.decayStats()
+
+	_, ok := pg.stats[peerA]
+	if ok {
+		t.Fatal("still have a stat record for peerA")
+	}
+}