Move add_admin_options() to stream_data.js.

This function used to live in subs.js.  It's mostly a code move,
but I simplified the logic to determine whether it's subscribed
not to do a lookup into the same data structure that the sub
already came from.

I also added some tests.

frontend_tests/node_tests/stream_data.js

@@ -5,6 +5,7 @@ add_dependencies({
 });
 
 set_global('blueslip', {});
+set_global('page_params', {is_admin: false});
 
 var stream_data = require('js/stream_data.js');
 
@@ -134,3 +135,55 @@ var stream_data = require('js/stream_data.js');
     assert.equal(stream_data.user_is_subscribed('Rome', email), undefined);
 
 }());
+
+(function test_admin_options() {
+    function make_sub() {
+        return {
+            subscribed: false,
+            color: 'blue',
+            name: 'stream_to_admin',
+            stream_id: 1,
+            in_home_view: false,
+            invite_only: false
+        };
+    }
+
+    // non-admins can't do anything
+    global.page_params.is_admin = false;
+    var sub = make_sub();
+    stream_data.add_admin_options(sub);
+    assert(!sub.is_admin);
+    assert(!sub.can_make_public);
+    assert(!sub.can_make_private);
+
+    // just a sanity check that we leave "normal" fields alone
+    assert.equal(sub.color, 'blue');
+
+    // the remaining cases are for admin users
+    global.page_params.is_admin = true;
+
+    // admins can make public streams become private
+    sub = make_sub();
+    stream_data.add_admin_options(sub);
+    assert(sub.is_admin);
+    assert(!sub.can_make_public);
+    assert(sub.can_make_private);
+
+    // admins can only make private streams become public
+    // if they are subscribed
+    sub = make_sub();
+    sub.invite_only = true;
+    sub.subscribed = false;
+    stream_data.add_admin_options(sub);
+    assert(sub.is_admin);
+    assert(!sub.can_make_public);
+    assert(!sub.can_make_private);
+
+    sub = make_sub();
+    sub.invite_only = true;
+    sub.subscribed = true;
+    stream_data.add_admin_options(sub);
+    assert(sub.is_admin);
+    assert(sub.can_make_public);
+    assert(!sub.can_make_private);
+}());

static/js/stream_data.js

@@ -209,6 +209,15 @@ exports.receives_audible_notifications = function (stream_name) {
     return sub.audible_notifications;
 };
 
+exports.add_admin_options = function (sub) {
+    return _.extend(sub, {
+        'is_admin': page_params.is_admin,
+        'can_make_public': page_params.is_admin && sub.invite_only && sub.subscribed,
+        'can_make_private': page_params.is_admin && !sub.invite_only
+    });
+};
+
+
 return exports;
 
 }());

static/js/subs.js

@@ -2,14 +2,6 @@ var subs = (function () {
 
 var exports = {};
 
-function add_admin_options(sub) {
-    return _.extend(sub, {
-        'is_admin': page_params.is_admin,
-        'can_make_public': page_params.is_admin && sub.invite_only && stream_data.is_subscribed(sub.name),
-        'can_make_private': page_params.is_admin && !sub.invite_only
-    });
-}
-
 function get_color() {
     var used_colors = stream_data.get_colors();
     var color = stream_color.pick_color(used_colors);
@@ -255,7 +247,7 @@ function add_email_hint(row, email_address_hint_content) {
 }
 
 function add_sub_to_table(sub) {
-    sub = add_admin_options(sub);
+    sub = stream_data.add_admin_options(sub);
     var html = templates.render('subscription', sub);
     $('#create_or_filter_stream_row').after(html);
     settings_for_sub(sub).collapse('show');
@@ -493,7 +485,7 @@ exports.setup_page = function () {
         // Add in admin options.
         var sub_rows = [];
         _.each(all_subs, function (sub) {
-            sub = add_admin_options(sub);
+            sub = stream_data.add_admin_options(sub);
             sub_rows.push(sub);
         });
 
@@ -1125,7 +1117,7 @@ $(function () {
     function redraw_privacy_related_stuff(sub_row, sub) {
         var html;
 
-        sub = add_admin_options(sub);
+        sub = stream_data.add_admin_options(sub);
 
         html = templates.render('subscription_setting_icon', sub);
         sub_row.find('.subscription-setting-icon').expectOne().html(html);