fix: define missing test helper func

Author: pkoutsovasilis

testing/integration/ess/upgrade_rollback_test.go

@@ -293,3 +293,48 @@ func TestStandaloneUpgradeRollbackOnRestarts(t *testing.T) {
 	err = upgradetest.CheckHealthyAndVersion(ctx, startFixture, startVersionInfo.Binary)
 	assert.NoError(t, err)
 }
+
+func restartAgentNTimes(t *testing.T, noOfRestarts int, sleepBetweenIterations time.Duration) {
+	topPath := paths.Top()
+
+	for restartIdx := 0; restartIdx < noOfRestarts; restartIdx++ {
+		time.Sleep(sleepBetweenIterations)
+
+		t.Logf("Stopping agent via service to simulate crashing")
+		err := install.StopService(topPath, install.DefaultStopTimeout, install.DefaultStopInterval)
+		if err != nil && runtime.GOOS == define.Windows && strings.Contains(err.Error(), "The service has not been started.") {
+			// Due to the quick restarts every 10 seconds its possible that this is faster than Windows
+			// can handle. Decrementing restartIdx means that the loop will occur again.
+			t.Logf("Got an allowed error on Windows: %s", err)
+			err = nil
+		}
+		require.NoError(t, err)
+
+		// ensure that it's stopped before starting it again
+		var status service.Status
+		var statusErr error
+		require.Eventuallyf(t, func() bool {
+			status, statusErr = install.StatusService(topPath)
+			if statusErr != nil {
+				return false
+			}
+			return status != service.StatusRunning
+		}, 5*time.Minute, 1*time.Second, "service never fully stopped (status: %v): %s", status, statusErr)
+		t.Logf("Stopped agent via service to simulate crashing")
+
+		// start it again
+		t.Logf("Starting agent via service to simulate crashing")
+		err = install.StartService(topPath)
+		require.NoError(t, err)
+
+		// ensure that it's started before next loop
+		require.Eventuallyf(t, func() bool {
+			status, statusErr = install.StatusService(topPath)
+			if statusErr != nil {
+				return false
+			}
+			return status == service.StatusRunning
+		}, 5*time.Minute, 1*time.Second, "service never fully started (status: %v): %s", status, statusErr)
+		t.Logf("Started agent via service to simulate crashing")
+	}
+}