tests: check post-condition using |getlist on block (#47715)

tests/form_pages/test_block.py

@@ -834,3 +834,39 @@ def test_block_digest_item(pub, blocks_feature):
             {'123': 'foo2', '234': '2', '234_display': 'deux'},
     ]
     assert formdef.data_class().select()[0].data['1_display'] == 'XunY, XdeuxY'
+
+
+def test_block_post_condition_on_2nd_page(pub, blocks_feature):
+    FormDef.wipe()
+    BlockDef.wipe()
+
+    block = BlockDef()
+    block.name = 'foobar'
+    block.fields = [
+        fields.StringField(id='123', required=True, label='Test', type='string', varname='foo'),
+    ]
+    block.store()
+
+    formdef = FormDef()
+    formdef.name = 'form title'
+    formdef.fields = [
+        fields.PageField(id='0', label='1st page', type='page'),
+        fields.PageField(id='1', label='2nd page', type='page', post_conditions=[{
+            'condition': {
+                'type': 'django', 'value': 'form_var_blockfoo|getlist:"foo"|sum == 5'
+            }, 'error_message': 'You shall not pass.'}]),
+        fields.BlockField(id='2', label='test', type='block:foobar', max_items=3,
+                          varname='blockfoo'),
+    ]
+    formdef.store()
+
+    app = get_app(pub)
+    resp = app.get(formdef.get_url())
+    resp = resp.form.submit('submit')  # -> second page
+    resp.form['f2$element0$f123'] = 2
+    resp = resp.form.submit('f2$add_element')
+    resp.form['f2$element1$f123'] = 3
+    resp = resp.form.submit('submit')  # -> validation page
+    assert 'You shall not pass.' not in resp.text
+    resp = resp.form.submit('submit')  # -> submit
+    resp = resp.follow()