diff --git a/tests/src/mocks/metric_mock.hpp b/tests/src/mocks/metric_mock.hpp
index a105aa0..268b681 100644
--- a/tests/src/mocks/metric_mock.hpp
+++ b/tests/src/mocks/metric_mock.hpp
@@ -20,4 +20,9 @@
     MOCK_METHOD(std::vector<MetricValue>, getReadings, (), (const, override));
     MOCK_METHOD(LabeledMetricParameters, dumpConfiguration, (),
                 (const, override));
+
+    uint64_t sensorCount() const override
+    {
+        return getReadings().size();
+    }
 };