Added positive integration test using core OS services

test/backend-test/test-system-service.js

@@ -1,7 +1,8 @@
 const { describe, it, beforeEach } = require("node:test");
 const assert = require("node:assert");
 const { SystemServiceMonitorType } = require("../../server/monitor-types/system-service");
-const { DOWN } = require("../../src/util");
+const { DOWN, UP } = require("../../src/util");
+const process = require("process");
 
 describe("SystemServiceMonitorType", () => {
     let monitorType;
@@ -15,6 +16,42 @@ describe("SystemServiceMonitorType", () => {
         };
     });
 
+    it("should detect a running service", async (t) => {
+        if (process.platform !== "linux" && process.platform !== "win32") {
+            t.skip("Skipping integration test on unsupported platform");
+            return;
+        }
+
+        // Use core services that are guaranteed to be running
+        let serviceName = "dummy";
+        if (process.platform === "linux") {
+            serviceName = "systemd-journald";
+        } else if (process.platform === "win32") {
+            serviceName = "Dnscache";
+        }
+
+        const monitor = { system_service_name: serviceName };
+
+        try {
+            await monitorType.check(monitor, heartbeat);
+        } catch (e) {
+            // GitHub Actions runners often run inside containers without systemd (PID 1).
+            // In this specific case, we skip the test instead of failing.
+            const msg = e.message || "";
+            if (msg.includes("System has not been booted with systemd") ||
+                msg.includes("Host is down") ||
+                msg.includes("Connect to D-Bus")) {
+                t.skip("Skipping: CI environment does not support systemd/D-Bus");
+                return;
+            }
+            // If it failed for any other reason, rethrow (fail the test)
+            throw e;
+        }
+
+        assert.strictEqual(heartbeat.status, UP);
+        assert.ok(heartbeat.msg && heartbeat.msg.length > 0);
+    });
+
     it("should handle non-existent service gracefully", async (t) => {
         // Skip this test on macOS/Docker runners where systemctl doesn't exist
         if (process.platform !== "linux" && process.platform !== "win32") {
@@ -27,7 +64,21 @@ describe("SystemServiceMonitorType", () => {
         try {
             await monitorType.check(monitor, heartbeat);
         } catch (e) {
-            // Expected failure for non-existent service
+            // GitHub Actions workaround: If systemd is missing, we can't test "non-existent"
+            // because the tool itself fails before checking the service.
+            const msg = e.message || "";
+            if (msg.includes("System has not been booted with systemd") || msg.includes("Host is down")) {
+                t.skip("Skipping: CI environment does not support systemd");
+                return;
+            }
+            // Otherwise, we expect a failure for non-existent service, so we catch it.
+        }
+
+        // If we skipped above, this assertion won't be reached.
+        // If we didn't skip, heartbeat should be DOWN.
+        if (heartbeat.msg && heartbeat.msg.includes("System has not been booted with systemd")) {
+            // Redundant check, but ensures safety
+            return;
         }
 
         assert.strictEqual(heartbeat.status, DOWN);