node tests: Directly test how we add/remove rtl class.

frontend_tests/node_tests/rtl.js

@@ -4,6 +4,7 @@ const {strict: assert} = require("assert");
 
 const {zrequire} = require("../zjsunit/namespace");
 const {run_test} = require("../zjsunit/test");
+const $ = require("../zjsunit/zjquery");
 
 const rtl = zrequire("rtl");
 
@@ -126,3 +127,22 @@ run_test("get_direction", () => {
         "ltr",
     );
 });
+
+run_test("set_rtl_class_for_textarea rtl", () => {
+    const textarea = $.create("some-textarea");
+    assert(!textarea.hasClass("rtl"));
+    const text = "```quote\nمرحبا";
+    textarea.val(text);
+    rtl.set_rtl_class_for_textarea(textarea);
+    assert(textarea.hasClass("rtl"));
+});
+
+run_test("set_rtl_class_for_textarea ltr", () => {
+    const textarea = $.create("some-textarea");
+    textarea.addClass("rtl");
+    assert(textarea.hasClass("rtl"));
+    const text = "```quote\nEnglish text";
+    textarea.val(text);
+    rtl.set_rtl_class_for_textarea(textarea);
+    assert(!textarea.hasClass("rtl"));
+});