Re-enable TestFQDN (#3911)

* Re-enable TestFQDN

* Add debugging statement

* Add convenience method

* Remove debugging statement

* Create new context as old one is already canceled

pkg/testing/tools/testcontext/testcontext.go

@@ -22,3 +22,14 @@ func WithDeadline(
 	ctx, cancel := context.WithDeadline(parent, deadline)
 	return ctx, cancel
 }
+
+// WithTimeout returns a context with a deadline calculated from the provided
+// timeout duration. It is the equivalent of calling WithDeadline with the
+// deadline specified as time.Now() + timeout.
+func WithTimeout(
+	t *testing.T,
+	parentCtx context.Context,
+	timeout time.Duration,
+) (context.Context, context.CancelFunc) {
+	return WithDeadline(t, parentCtx, time.Now().Add(timeout))
+}

testing/integration/fqdn_test.go

@@ -41,7 +41,6 @@ func TestFQDN(t *testing.T) {
 		Local: false,
 		Sudo:  true,
 	})
-	t.Skip("Flaky test, see https://github.com/elastic/elastic-agent/issues/3154")
 
 	agentFixture, err := define.NewFixture(t, define.Version())
 	require.NoError(t, err)
@@ -96,6 +95,9 @@ func TestFQDN(t *testing.T) {
 		assert.NoError(t, fleettools.UnEnrollAgent(info.KibanaClient, policy.ID))
 
 		t.Log("Restoring hostname...")
+		ctx, cancel := testcontext.WithTimeout(t, context.Background(), 1*time.Minute)
+		defer cancel()
+
 		err := setHostname(ctx, origHostname, t.Log)
 		require.NoError(t, err)