Add test for double widgets in a form

tests/src/python/CMakeLists.txt

@@ -17,6 +17,7 @@ ADD_PYTHON_TEST(PyQgsAggregateCalculator test_qgsaggregatecalculator.py)
 ADD_PYTHON_TEST(PyQgsAnnotation test_qgsannotation.py)
 ADD_PYTHON_TEST(PyQgsApplication test_qgsapplication.py)
 ADD_PYTHON_TEST(PyQgsAttributeFormEditorWidget test_qgsattributeformeditorwidget.py)
+ADD_PYTHON_TEST(PyQgsAttributeForm test_qgsattributeform.py)
 ADD_PYTHON_TEST(PyQgsAttributeTableConfig test_qgsattributetableconfig.py)
 ADD_PYTHON_TEST(PyQgsAttributeTableModel test_qgsattributetablemodel.py)
 ADD_PYTHON_TEST(PyQgsAuthenticationSystem test_qgsauthsystem.py)

tests/src/python/test_qgsattributeform.py

@@ -0,0 +1,120 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for the attribute form
+
+
+Run with ctest -V -R PyQgsAttributeForm
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+"""
+__author__ = 'Alessandro Pasotti'
+__date__ = '2019-06-06'
+__copyright__ = 'Copyright 2019, The QGIS Project'
+
+
+from qgis.testing import start_app, unittest
+from qgis.core import (
+    QgsFields,
+    QgsVectorLayer,
+    QgsFeature,
+    QgsEditorWidgetSetup,
+    QgsEditFormConfig,
+    QgsAttributeEditorElement,
+)
+from qgis.gui import (
+    QgsAttributeForm,
+    QgsGui,
+    QgsEditorWidgetWrapper,
+)
+
+
+QGISAPP = start_app()
+
+
+class TestQgsAttributeForm(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        QgsGui.editorWidgetRegistry().initEditors()
+
+    @classmethod
+    def createLayerWithOnePoint(cls, field_type):
+        layer = QgsVectorLayer("Point?field=fld:%s" % field_type,
+                               "vl", "memory")
+        pr = layer.dataProvider()
+        f = QgsFeature()
+        assert pr.addFeatures([f])
+        assert layer.featureCount() == 1
+        return layer
+
+    @classmethod
+    def createFormWithDuplicateWidget(cls, vl, field_type, widget_type):
+        """Creates a form with two identical widgets for the same field"""
+
+        config = vl.editFormConfig()
+        config.setLayout(QgsEditFormConfig.TabLayout)
+        element = config.tabs()[0]
+        element2 = element.clone(element)
+        config.addTab(element2)
+        vl.setEditFormConfig(config)
+        vl.setEditorWidgetSetup(0, QgsEditorWidgetSetup(widget_type, {}))
+        form = QgsAttributeForm(vl, next(vl.getFeatures()))
+        assert (form.editable())
+        return form
+
+    @classmethod
+    def get_widgets_for_field(cls, vl):
+        """Get compatible widget names"""
+
+        return [k for k, v in QgsGui.editorWidgetRegistry().factories().items() if v.supportsField(vl, 0)]
+
+    @classmethod
+    def checkForm(cls, field_type, value):
+        """Creates a vector layer and an associated form with two identical widgets for the same field and test it with NULL and after setting a value
+        """
+
+        vl = cls.createLayerWithOnePoint(field_type)
+        assert (vl.startEditing())
+        for widget_type in cls.get_widgets_for_field(vl):
+            form = cls.createFormWithDuplicateWidget(vl, field_type, widget_type)
+            vl.changeAttributeValue(1, 0, value)
+            form.setFeature(next(vl.getFeatures()))
+
+    def test_duplicated_widgets(self):
+        """
+        Note: this crashed two times for datetime (see GH #29937):
+
+        - first crash with inital NULL values, because widget's clear() triggered changed()
+        - second crash when setting a value, because setDateTime() triggered changed()
+
+        There are no assertions in this test because we are looking for a crash.
+        """
+
+        field_types = {
+            'integer': 123,
+            'double': 123.45,
+            'string': 'lorem ipsum',
+            'date': '2019-01-01',
+            'time': '12:12:12',
+            'datetime': '2019-01-01',
+            'int2': 123,
+            'int4': 123,
+            'int8': 123,
+            'numeric': 123.45,
+            'decimal': 123.45,
+            'real': 123.45,
+            'double precision': 123.45,
+            'text': 'lorem ipsum',
+            'bool': True,
+            #'binary'
+        }
+
+        for field_type, value in field_types.items():
+            self.checkForm(field_type, value)
+
+
+if __name__ == '__main__':
+    unittest.main()