fix: monitor graph gaps for sub-millisecond TCP pings (#7159)

src/components/PingChart.vue

@@ -310,15 +310,15 @@ export default {
             // Show ping values if it was up in this period
             avgPingData.push({
                 x,
-                y: datapoint.up > 0 && datapoint.avgPing > 0 ? datapoint.avgPing : null,
+                y: datapoint.up > 0 && datapoint.avgPing != null ? datapoint.avgPing : null,
             });
             minPingData.push({
                 x,
-                y: datapoint.up > 0 && datapoint.avgPing > 0 ? datapoint.minPing : null,
+                y: datapoint.up > 0 && datapoint.avgPing != null ? datapoint.minPing : null,
             });
             maxPingData.push({
                 x,
-                y: datapoint.up > 0 && datapoint.avgPing > 0 ? datapoint.maxPing : null,
+                y: datapoint.up > 0 && datapoint.avgPing != null ? datapoint.maxPing : null,
             });
             downData.push({
                 x,

test/backend-test/test-ping-chart.js

@@ -0,0 +1,50 @@
+const { describe, test } = require("node:test");
+const assert = require("node:assert");
+
+/**
+ * Extracts the ping value filtering logic from PingChart.vue pushDatapoint().
+ * This mirrors the condition: datapoint.up > 0 && datapoint.avgPing != null
+ * @param {object} datapoint Datapoint with up, avgPing, minPing, maxPing
+ * @returns {number|null} The avgPing value or null if filtered out
+ */
+function filterPingValue(datapoint) {
+    return datapoint.up > 0 && datapoint.avgPing != null ? datapoint.avgPing : null;
+}
+
+describe("PingChart pushDatapoint filtering", () => {
+    test("avgPing of 0 should be rendered, not filtered out (#7143)", () => {
+        const datapoint = { up: 1, down: 0, avgPing: 0, minPing: 0, maxPing: 0 };
+        const result = filterPingValue(datapoint);
+        assert.strictEqual(result, 0, "avgPing of 0 must not be converted to null");
+    });
+
+    test("avgPing of 1 should be rendered", () => {
+        const datapoint = { up: 1, down: 0, avgPing: 1, minPing: 1, maxPing: 1 };
+        const result = filterPingValue(datapoint);
+        assert.strictEqual(result, 1);
+    });
+
+    test("avgPing of null should be filtered out", () => {
+        const datapoint = { up: 1, down: 0, avgPing: null, minPing: null, maxPing: null };
+        const result = filterPingValue(datapoint);
+        assert.strictEqual(result, null);
+    });
+
+    test("avgPing of undefined should be filtered out", () => {
+        const datapoint = { up: 1, down: 0, avgPing: undefined, minPing: undefined, maxPing: undefined };
+        const result = filterPingValue(datapoint);
+        assert.strictEqual(result, null);
+    });
+
+    test("datapoint with no up counts should be filtered out", () => {
+        const datapoint = { up: 0, down: 1, avgPing: 5, minPing: 5, maxPing: 5 };
+        const result = filterPingValue(datapoint);
+        assert.strictEqual(result, null);
+    });
+
+    test("normal ping value with up count should be rendered", () => {
+        const datapoint = { up: 3, down: 0, avgPing: 42, minPing: 30, maxPing: 55 };
+        const result = filterPingValue(datapoint);
+        assert.strictEqual(result, 42);
+    });
+});