[VC-35738] Append errgroup errors to the error returned by Agent.Run (#606)

* Append errgroup errors to Run return error
* Fail TestRunOneShot if Run returns errors

Author: wallrj

pkg/agent/run.go

@@ -50,7 +50,7 @@ var Flags AgentCmdFlags
 const schemaVersion string = "v2.0.0"
 
 // Run starts the agent process
-func Run(cmd *cobra.Command, args []string) error {
+func Run(cmd *cobra.Command, args []string) (returnErr error) {
 	logs.Log.Printf("Preflight agent version: %s (%s)", version.PreflightVersion, version.Commit)
 	ctx, cancel := context.WithCancel(
 		klog.NewContext(
@@ -85,8 +85,8 @@ func Run(cmd *cobra.Command, args []string) error {
 	defer func() {
 		cancel()
 		if groupErr := group.Wait(); groupErr != nil {
-			err = multierror.Append(
-				err,
+			returnErr = multierror.Append(
+				returnErr,
 				fmt.Errorf("failed to wait for controller-runtime component to stop: %v", groupErr),
 			)
 		}

pkg/agent/run_test.go

@@ -44,8 +44,11 @@ func TestRunOneShot(t *testing.T) {
 		require.NoError(t, err)
 
 		logs.Initialize()
-		Run(c, nil)
-		klog.Flush()
+		defer klog.Flush()
+
+		runErr := Run(c, nil)
+		require.NoError(t, runErr, "Run returned an unexpected error")
+
 		return
 	}
 	t.Log("Running child process")