Restrict number of users input to positive numbers

When a customer enters information about evaluating
the trial we should restrict possible values for
number of users field to 1 or greater.

ee/app/views/trials/new.html.haml

@@ -20,7 +20,7 @@
     = text_field_tag :phone_number, params[:phone_number], class: 'form-control', required: true
   .form-group
     = label_tag :number_of_users, _('How many users will be evaluating the trial?'), for: :number_of_users, class: 'col-form-label'
-    = number_field_tag :number_of_users, nil, class: 'form-control', required: true
+    = number_field_tag :number_of_users, nil, class: 'form-control', required: true, min: 1
   .form-group
     = label_tag :country, _('Country'), class: 'col-form-label'
     = select_tag :country, options_for_select([[_('Please select a country'), '']]), class: 'select2', required: true, id: 'country_select', data: { countries_end_point: countries_path }

ee/spec/features/trials/capture_lead_spec.rb

@@ -41,27 +41,38 @@ describe 'Trial Capture Lead', :js do
       end
     end
 
-    context 'enters invalid company information' do
+    context 'enters company information' do
       before do
         fill_in 'company_name', with: 'GitLab'
         select2 '1-99', from: '#company_size'
-        # to trigger validation error
-        # skip filling phone number
-        # fill_in 'phone_number', with: '+1234567890'
         fill_in 'number_of_users', with: '1'
         select2 'US', from: '#country_select'
-
-        click_button 'Continue'
       end
 
-      it 'shows validation error' do
-        message = page.find('#phone_number').native.attribute('validationMessage')
+      context 'without phone number' do
+        it 'shows validation error' do
+          fill_in 'number_of_users', with: '1'
+
+          click_button 'Continue'
 
-        expect(message).to eq('Please fill out this field.')
+          message = page.find('#phone_number').native.attribute('validationMessage')
+
+          expect(message).to eq('Please fill out this field.')
+          expect(current_path).to eq(new_trial_path)
+        end
       end
 
-      it 'does not proceeds to the next step' do
-        expect(current_path).to eq(new_trial_path)
+      context 'and enters negative number to the number of users field' do
+        it 'shows validation error' do
+          fill_in 'number_of_users', with: '-1'
+
+          click_button 'Continue'
+
+          message = page.find('#number_of_users').native.attribute('validationMessage')
+
+          expect(message).to eq('Value must be greater than or equal to 1.')
+          expect(current_path).to eq(new_trial_path)
+        end
       end
     end
   end