use assert equals

src/__tests__/casperjs/helper_bar_intl_test.js

@@ -35,7 +35,10 @@ casper.start(
         return debug_Intl_getLocale();
       });
       // Successfully changed locale
-      this.test.assert(locale === 'ja');
+      this.test.assertEquals(
+        locale,
+        'ja'
+      );
     })
     .then(CasperUtils.testDone);
 }).run();

src/__tests__/casperjs/level_objective_test.js

@@ -28,8 +28,9 @@ casper.start(
       var text = this.evaluate(function() {
         return document.querySelector('div.inside > div > p').innerText;
       });
-      this.test.assert(
+      this.test.assertEquals(
-        text === "Go ahead and try it out on your own! After this " +
+        text,
+        "Go ahead and try it out on your own! After this " +
           "window closes, make two commits to complete the level"
       );
     })

src/__tests__/casperjs/level_show_goal_test.js

@@ -25,8 +25,9 @@ casper.start(
       var text = this.evaluate(function() {
         return document.querySelector('p.helperText').innerText;
       });
-      this.test.assert(
+      this.test.assertEquals(
-        text === 'You can hide this window with "hide goal"'
+        text,
+        'You can hide this window with "hide goal"'
       );
     })
     .then(CasperUtils.testDone);