Add tests for text-direction functions

test/javascripts/lib/text-direction-test.js.es6

@@ -0,0 +1,23 @@
+import { isRTL, isLTR, setTextDirections, siteDir } from 'discourse/lib/text-direction';
+
+QUnit.module('lib:text-direction');
+
+QUnit.test("isRTL", assert => {
+  // Hebrew
+  assert.equal(isRTL('זה מבחן'), true);
+
+  // Arabic
+  assert.equal(isRTL('هذا اختبار'), true);
+
+  // Persian
+  assert.equal(isRTL('این یک امتحان است'), true);
+
+  assert.equal(isRTL('This is a test'), false);
+  assert.equal(isRTL(''), false);
+});
+
+QUnit.test("isLTR", assert => {
+  assert.equal(isLTR('This is a test'), true);
+  assert.equal(isLTR('זה מבחן'), false);
+});
+