add test for cache miss

cache/cache_test.go

@@ -32,3 +32,18 @@ func TestCacheGet(t *testing.T) {
 		t.Fatalf("cache.Get(\"1.2.3.4\") = %f, want %f", score.Score, testFloat)
 	}
 }
+
+func TestCacheMiss(t *testing.T) {
+	now := time.Now()
+	const testFloat = 1.23456
+
+	expiredTime := now.Add(-(time.Minute * 10))
+
+	cache := NewLocalCache()
+	cache.Add(testFloat, netip.MustParseAddr("1.2.3.4"), expiredTime)
+
+	_, err := cache.Get(netip.MustParseAddr("1.2.3.4"))
+	if err == nil {
+		t.Fatalf("cache.Get(\"1.2.3.4\") = got nil, want error")
+	}
+}