[FIX] web: ModelFieldSelector: add a way to clear the cache

The ModelFieldSelector keeps an internal cache for the fields_get.
This cache needs to be cleared in the tests environment because
a model with the same name may be defined several times accross the
tests modules, but they may contain different fields.

This could also be a problem with studio: when a field is created,
the ModelFieldSelector cache must be cleared as well (in addition
to the data_manager one).

We thus introduce a new 'clear_cache' event on core.bus. When
triggered, the ModelFieldSelector and the data_manager clear their
respective cache.

We use this event in the test environment to ensure that the cache
is cleared at the end of each test using a mockEnvironment. This
rev. also fixes an infinite loop in the override of destroy() in
the mockEnvironment, which occured when both session and config
were specified in the params.

addons/web/static/src/js/services/data_manager.js

@@ -11,6 +11,7 @@ var utils = require('web.utils');
 return core.Class.extend({
     init: function () {
         this._init_cache();
+        core.bus.on('clear_cache', this, this.invalidate.bind(this));
     },
 
     _init_cache: function () {

addons/web/static/src/js/widgets/model_field_selector.js

@@ -16,6 +16,11 @@ var modelFieldsCache = {
     cacheDefs: {},
 };
 
+core.bus.on('clear_cache', null, function () {
+    modelFieldsCache.cache = {};
+    modelFieldsCache.cacheDefs = {};
+});
+
 /**
  * The ModelFieldSelector widget can be used to display/select a particular
  * field chain from a given model.

addons/web/static/tests/helpers/test_utils.js

@@ -252,52 +252,53 @@ function addMockEnvironment(widget, params) {
         logLevel: params.logLevel,
         currentDate: params.currentDate,
     });
-    var widgetDestroy;
-
     // make sure the debounce value for input fields is set to 0
     var initialDebounce = DebouncedField.prototype.DEBOUNCE;
     DebouncedField.prototype.DEBOUNCE = params.fieldDebounce || 0;
-
+    var initialSession, initialConfig, initialParameters;
     if ('session' in params) {
-        var initialSession = _.extend({}, session);
+        initialSession = _.extend({}, session);
         _.extend(session, params.session);
-        widgetDestroy = widget.destroy;
-        widget.destroy = function () {
-            for (var key in session) {
+    }
+    if ('config' in params) {
+        initialConfig = _.extend({}, config);
+        _.extend(config, params.config);
+    }
+    if ('translateParameters' in params) {
+        initialParameters = _.extend({}, core._t.database.parameters);
+        _.extend(core._t.database.parameters, params.translateParameters);
+    }
+
+    var widgetDestroy = widget.destroy;
+    widget.destroy = function () {
+        // clear the caches (e.g. data_manager, ModelFieldSelector) when the
+        // widget is destroyed, at the end of each test to avoid collisions
+        core.bus.trigger('clear_cache');
+
+        DebouncedField.prototype.DEBOUNCE = initialDebounce;
+
+        var key;
+        if ('session' in params) {
+            for (key in session) {
                 delete session[key];
             }
             _.extend(session, initialSession);
-            widgetDestroy.call(this);
-        };
-    }
-
-    if ('config' in params) {
-        var initialConfig = _.extend({}, config);
-        _.extend(config, params.config);
-        widgetDestroy = widget.destroy;
-        widget.destroy = function () {
-            for (var key in config) {
+        }
+        if ('config' in params) {
+            for (key in config) {
                 delete config[key];
             }
             _.extend(config, initialConfig);
-            DebouncedField.prototype.DEBOUNCE = initialDebounce;
-            widgetDestroy.call(this);
-        };
-    }
-
-    if ('translateParameters' in params) {
-        var initialParameters = _.extend({}, core._t.database.parameters);
-        _.extend(core._t.database.parameters, params.translateParameters);
-        var oldDestroy = widget.destroy;
-        widget.destroy = function () {
-            for (var key in core._t.database.parameters) {
+        }
+        if ('translateParameters' in params) {
+            for (key in core._t.database.parameters) {
                 delete core._t.database.parameters[key];
             }
             _.extend(core._t.database.parameters, initialParameters);
-            oldDestroy.call(this);
-        };
-    }
+        }
 
+        widgetDestroy.call(this);
+    };
 
     intercept(widget, 'call_service', function (event) {
         if (event.data.service === 'ajax') {