Added a wait for the loading spinner to disappear when tapping next a…

…fter you type the email.

It looks like some tests are failing because it tries to click the sign in button while the spinner is still displayed.

browserid/pages/sign_in.py

@@ -15,6 +15,7 @@
 class SignIn(Base):
 
     _form_completing_loading_locator = (By.CSS_SELECTOR, '.form.completing.loading')
+    _checking_email_provider_loading_locator = (By.CSS_SELECTOR, '#load .loadingSpinner')
     _this_is_not_me_locator = (By.CSS_SELECTOR, '.isDesktop.thisIsNotMe')
     _signed_in_email_locator = (By.CSS_SELECTOR, 'label[for=email_0]')
     _emails_locator = (By.CSS_SELECTOR, 'label[for^=email_]')
@@ -171,6 +172,10 @@ def click_next(self, expect='password'):
         else:
             self.selenium.find_element(*self._mobile_next_locator).click()
 
+        WebDriverWait(self.selenium, self.timeout).until(
+            lambda s: not s.find_element(
+                *self._checking_email_provider_loading_locator).is_displayed())
+
         if expect == 'password':
             WebDriverWait(self.selenium, self.timeout).until(
                 lambda s: s.find_element(