Address review comments

command/agent/config_parse.go

@@ -1015,9 +1015,8 @@ func parsePlugins(result *[]*config.PluginConfig, list *ast.ObjectList) error {
 		listVal := list.Items[i]
 
 		// Deal with json->hcl AST parsing incorrectness when directly nested
-		// items show up as additional keys. This currently only affects plugin
-		// configuration because args is not necessary. All other fields in the config
-		// have multiple keys and parse from json into the AST correctly.
+		// items show up as additional keys.
+		// TODO(preetha): Add additional tests and fix other places that have the same issue
 		unwrapLegacyHCLObjectKeysFromJSON(listVal, 1)
 		if err := helper.CheckHCLKeys(listVal.Val, valid); err != nil {
 			return fmt.Errorf("invalid keys in plugin config %d: %v", i+1, err)

command/agent/config_parse_test.go

@@ -657,7 +657,7 @@ func TestConfig_Parse(t *testing.T) {
 	for _, tc := range cases {
 		t.Run(tc.File, func(t *testing.T) {
 			require := require.New(t)
-			path, err := filepath.Abs(filepath.Join("./config-test-fixtures", tc.File))
+			path, err := filepath.Abs(filepath.Join("./testdata", tc.File))
 			if err != nil {
 				t.Fatalf("file: %s\n\n%s", tc.File, err)
 			}

command/agent/testdata/basic.hcl

@@ -1,3 +1,4 @@
+# This file was used to generate basic.json from https://www.hcl2json.com/
 region = "foobar"
 datacenter = "dc2"
 name = "my-web"