diff --git a/frontend_tests/node_tests/subs.js b/frontend_tests/node_tests/subs.js
index 35da3d6b69..265079cc8b 100644
--- a/frontend_tests/node_tests/subs.js
+++ b/frontend_tests/node_tests/subs.js
@@ -7,6 +7,8 @@ add_dependencies({
     i18n: 'i18next',
 });
 
+set_global('channel', {});
+
 var subs = require('js/subs.js');
 
 var jsdom = require("jsdom");
@@ -160,3 +162,38 @@ subs.stream_description_match_stream_ids = [];
     assert.equal(subs.stream_name_match_stream_ids[1], 2);
 }());
 
+(function test_sub_or_unsub() {
+    var denmark = {
+        subscribed: false,
+        name: 'Denmark',
+        stream_id: 1,
+        description: 'Copenhagen',
+    };
+    stream_data.clear_subscriptions();
+    stream_data.add_sub("Denmark", denmark);
+
+    var post_params;
+
+    global.channel.post = function (params) {
+        post_params = params;
+    };
+
+    subs.sub_or_unsub(denmark.name);
+    assert.equal(post_params.url, '/json/users/me/subscriptions');
+    assert.deepEqual(post_params.data,
+        {subscriptions: '[{"name":"Denmark"}]'});
+
+    global.channel.post = undefined;
+
+    global.channel.del = function (params) {
+        post_params = params;
+    };
+
+    stream_data.get_sub_by_id(denmark.stream_id).subscribed = true;
+    subs.sub_or_unsub(denmark.name);
+    assert.equal(post_params.url, '/json/users/me/subscriptions');
+    assert.deepEqual(post_params.data,
+        {subscriptions: '["Denmark"]'});
+
+}());
+
diff --git a/static/js/subs.js b/static/js/subs.js
index 2072764b68..5199c23c43 100644
--- a/static/js/subs.js
+++ b/static/js/subs.js
@@ -1051,6 +1051,17 @@ exports.change_stream_name = function (e) {
     });
 };
 
+exports.sub_or_unsub = function (stream_name) {
+    var sub = stream_data.get_sub(stream_name);
+
+    if (sub.subscribed) {
+        ajaxUnsubscribe(stream_name);
+    } else {
+        ajaxSubscribe(stream_name);
+    }
+};
+
+
 $(function () {
 
     stream_data.initialize_from_page_params();
@@ -1262,19 +1273,9 @@ $(function () {
         selectText(this);
     });
 
-    function sub_or_unsub(stream_name) {
-        var sub = stream_data.get_sub(stream_name);
-
-        if (sub.subscribed) {
-            ajaxUnsubscribe(stream_name);
-        } else {
-            ajaxSubscribe(stream_name);
-        }
-    }
-
     $("#subscriptions_table").on("click", ".sub_unsub_button", function (e) {
         var stream_name = get_stream_name(e.target);
-        sub_or_unsub(stream_name);
+        exports.sub_or_unsub(stream_name);
         e.preventDefault();
         e.stopPropagation();
     });
@@ -1285,7 +1286,7 @@ $(function () {
 
         var stream_name = $(e.target).data("name");
 
-        sub_or_unsub(stream_name);
+        exports.sub_or_unsub(stream_name);
         e.preventDefault();
         e.stopPropagation();
     });