backoffice: add prefill using user selected in sidebar (#48983)

tests/backoffice_pages/test_submission.py

@@ -1297,6 +1297,7 @@ def test_backoffice_submission_user_selection(pub):
     for i in range(10):
         random_user = pub.user_class()
         random_user.name = 'random user %s' % i
+        random_user.email = 'test%s@invalid' % i
         random_user.store()
 
     FormDef.wipe()
@@ -1355,3 +1356,22 @@ def test_backoffice_submission_user_selection(pub):
     formdata_no = resp.location.split('/')[-2]
     data_class = formdef.data_class()
     assert data_class.get(formdata_no).user.name == random_user.name
+
+    # check prefill
+    formdef.fields[-1].prefill = {'type': 'user', 'value': 'email'}
+    formdef.store()
+
+    resp = app.get('/backoffice/submission/')
+    resp = resp.click(formdef.name)
+
+    assert resp.form['submission_channel'].attrs['type'] == 'hidden'
+    assert resp.pyquery('.submit-user-selection')
+    resp.form['user_id'] = str(random_user.id)  # happens via javascript
+    resp.form['f1'] = 'test submission'
+    resp = resp.form.submit('submit')  # -> 2nd page
+    assert not resp.pyquery('.submit-user-selection')
+    assert '>%s</p>' % random_user.name in resp
+    assert resp.form['f3'].value == random_user.email
+    resp = resp.form.submit('submit')  # -> validation page
+    assert 'Check values then click submit.' in resp
+    assert '<p>%s</p>' % random_user.name in resp

wcs/backoffice/submission.py

@@ -140,6 +140,12 @@ class FormFillPage(PublicFormFillPage):
         self.selected_user_id = get_request().form.get('user_id')
         return super(FormFillPage, self)._q_index(*args, **kwargs)
 
+    def get_transient_formdata(self, magictoken=Ellipsis):
+        formdata = super().get_transient_formdata(magictoken=magictoken)
+        if self.selected_user_id:
+            formdata.user_id = self.selected_user_id
+        return formdata
+
     def html_top(self, *args, **kwargs):
         return html_top('submission', *args, **kwargs)