[MM-19102] Enable debug flag for plugin check tests (#12588)

plugin/checker/main_test.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -35,6 +36,11 @@ func TestRunCheck(t *testing.T) {
 		},
 	}
 
+	// Enable debug flag to have packagesdriver/sizes.go print stderr of `go list` command.
+	// We want to surface any error text that may exist in stderr of this command.
+	prevEnvValue := os.Getenv("GOPACKAGESPRINTGOLISTERRORS")
+	os.Setenv("GOPACKAGESPRINTGOLISTERRORS", "true")
+
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			err := runCheck(tc.pkgPath)
@@ -46,4 +52,5 @@ func TestRunCheck(t *testing.T) {
 			}
 		})
 	}
+	os.Setenv("GOPACKAGESPRINTGOLISTERRORS", prevEnvValue)
 }