test: fix TestConfigFileDeprecatedOptions

Use minimal config struct for YAML marshaling.
Replace custom mapToSortedSlice with standard library functions.
Fix flag verification for deprecated experimental options.

Fixes etcd-io#19066

Signed-off-by: mansoora <[email protected]>

server/etcdmain/config_test.go

@@ -25,9 +25,9 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"sigs.k8s.io/yaml"
 
-	"github.com/stretchr/testify/assert"
 	"go.etcd.io/etcd/pkg/v3/featuregate"
 	"go.etcd.io/etcd/pkg/v3/flags"
 	"go.etcd.io/etcd/server/v3/embed"
@@ -727,12 +727,15 @@ func TestConfigFileDeprecatedOptions(t *testing.T) {
 			}
 
 			// Compare sets of flags
-			assert.Equal(t, tc.expectedFlags, foundFlags, "deprecated flags mismatch")
+			assert.Equalf(t, tc.expectedFlags, foundFlags, "deprecated flags mismatch - expected: %v, got: %v",
+				tc.expectedFlags, foundFlags)
 
 			// Note: experimental-warning-unary-request-duration deprecation is handled
 			// through a separate mechanism in embed.Config
 			if tc.configFileYAML.ExperimentalWarningUnaryRequestDuration != 0 {
-				// Skip checking this flag as it's handled differently
+				assert.Equal(t, cfg.ec.WarningUnaryRequestDuration,
+					tc.configFileYAML.ExperimentalWarningUnaryRequestDuration,
+					"experimental warning duration should match")
 			}
 		})
 	}