[IMP] test_themes: add a test for the _post_copy() community fix

Now, `_post_copy()` is only called when the module is installed for the
first time on a website, not when the module is updated.

See counterpart commit in community for more details.

opw-2824045

closes odoo/design-themes#562

Related: odoo/odoo#91012
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

test_themes/tests/__init__.py

@@ -2,3 +2,4 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from . import test_crawl
+from . import test_theme_upgrade

test_themes/tests/test_theme_upgrade.py

@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+
+from odoo.addons.website.tools import MockRequest
+from odoo.tests import standalone
+
+
+@standalone('theme_upgrade', 'website_standalone')
+def test_01_theme_upgrade_post_copy(env):
+    """ This test ensures the theme `_post_copy()` method is only called when a
+    theme is installed for the first time on a website and not when the theme is
+    updated on that website.
+    """
+    # 1. Setup
+    website = env['website'].search([], limit=1)
+    Website = env['website'].with_context(website_id=website.id)
+
+    # Get rid of as many website as we can, any website will drastically slows
+    # down the test as when updating Theme Nano, it will update Theme Common
+    # which is applied on every site having a theme. It will then update all
+    # those websites.
+    Website.get_test_themes_websites().unlink()
+    for w in Website.search([('theme_id', '!=', False), ('id', '!=', website.id)]):
+        try:
+            w.unlink()
+        except Exception:
+            pass
+
+    ripple_specific_view = Website.viewref('website.option_ripple_effect')
+    fls_specific_view = Website.viewref('portal.footer_language_selector')
+    theme_nano_module = env.ref('base.module_theme_nano')
+
+    def _simulate_user_manual_change():
+        # Change some website options that will be changed by Theme Nano
+        ripple_specific_view.active = False
+        fls_specific_view.active = True
+
+    # 2. Simulate some website option change made by the user
+    _simulate_user_manual_change()
+
+    # 3. Simulate user choosing a new theme for his website
+    with MockRequest(env, website=website):
+        theme_nano_module.with_context(website_id=website.id).button_choose_theme()
+
+    assert Website.viewref('website.option_ripple_effect').active is True, \
+        "Theme Nano custo should be applied"
+    assert Website.viewref('portal.footer_language_selector').active is False, \
+        "Theme Nano custo should be applied (2)"
+
+    # 4. Simulate some website option change made by the user, again
+    _simulate_user_manual_change()
+
+    # 5. Upgrade Theme Nano
+    theme_nano_module.button_immediate_upgrade()
+    env.reset()  # clear the set of environments
+    env = env()  # get an environment that refers to the new registry
+
+    assert Website.viewref('website.option_ripple_effect').active is False, \
+        "Theme Nano custo should NOT be applied"
+    assert Website.viewref('portal.footer_language_selector').active is True, \
+        "Theme Nano custo should NOT be applied (2)"