Add unit tests for QgsVectorFileWriterTask

Author: nyalldawson

src/core/qgsvectorfilewritertask.cpp

@@ -29,7 +29,8 @@ QgsVectorFileWriterTask::QgsVectorFileWriterTask( QgsVectorLayer* layer, const Q
     mOwnedFeedback.reset( new QgsFeedback() );
     mOptions.feedback = mOwnedFeedback.get();
   }
-  setDependentLayers( QStringList() << mLayer->id() );
+  if ( mLayer )
+    setDependentLayers( QStringList() << mLayer->id() );
 }
 
 void QgsVectorFileWriterTask::cancel()
@@ -43,7 +44,6 @@ bool QgsVectorFileWriterTask::run()
   if ( !mLayer )
     return false;
 
-
   mError = QgsVectorFileWriter::writeAsVectorFormat(
              mLayer, mDestFileName, mOptions, &mNewFilename, &mErrorMessage );
   return mError == QgsVectorFileWriter::NoError;

tests/src/python/CMakeLists.txt

@@ -125,6 +125,7 @@ ADD_PYTHON_TEST(PyQgsTreeWidgetItem test_qgstreewidgetitem.py)
 ADD_PYTHON_TEST(PyQgsUnitTypes test_qgsunittypes.py)
 ADD_PYTHON_TEST(PyQgsVectorColorRamp test_qgsvectorcolorramp.py)
 ADD_PYTHON_TEST(PyQgsVectorFileWriter test_qgsvectorfilewriter.py)
+ADD_PYTHON_TEST(PyQgsVectorFileWriterTask test_qgsvectorfilewritertask.py)
 ADD_PYTHON_TEST(PyQgsVectorLayer test_qgsvectorlayer.py)
 ADD_PYTHON_TEST(PyQgsVectorLayerEditBuffer test_qgsvectorlayereditbuffer.py)
 ADD_PYTHON_TEST(PyQgsVectorLayerUtils test_qgsvectorlayerutils.py)

tests/src/python/test_qgsvectorfilewritertask.py

@@ -0,0 +1,126 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsVectorFileWriterTask.
+
+.. 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__ = 'Nyall Dawson'
+__date__ = '12/02/2017'
+__copyright__ = 'Copyright 2017, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+import qgis  # NOQA
+import os
+
+from qgis.core import (
+    QgsTask,
+    QgsTaskManager,
+    QgsApplication,
+    QgsVectorLayer,
+    QgsFeature,
+    QgsGeometry,
+    QgsPoint,
+    QgsVectorFileWriter,
+    QgsVectorFileWriterTask
+
+)
+from qgis.PyQt.QtCore import (QCoreApplication,
+                              QDir)
+
+from qgis.testing import start_app, unittest
+
+start_app()
+
+
+def create_temp_filename(base_file):
+    return os.path.join(str(QDir.tempPath()), base_file)
+
+
+class TestQgsVectorFileWriterTask(unittest.TestCase):
+
+    def setUp(self):
+        self.success = False
+        self.fail = False
+
+    def onSuccess(self):
+        self.success = True
+
+    def onFail(self):
+        self.fail = True
+
+    def createLayer(self):
+        layer = QgsVectorLayer(
+            ('Point?crs=epsg:4326&field=name:string(20)&'
+             'field=age:integer&field=size:double&index=yes'),
+            'test',
+            'memory')
+
+        self.assertIsNotNone(layer, 'Provider not initialized')
+        provider = layer.dataProvider()
+        self.assertIsNotNone(provider)
+
+        ft = QgsFeature()
+        ft.setGeometry(QgsGeometry.fromPoint(QgsPoint(10, 10)))
+        ft.setAttributes(['Johny', 20, 0.3])
+        provider.addFeatures([ft])
+        return layer
+
+    def testSuccess(self):
+        """test successfully writing a layer"""
+        self.layer = self.createLayer()
+        options = QgsVectorFileWriter.SaveVectorOptions()
+        tmp = create_temp_filename('successlayer.shp')
+        task = QgsVectorFileWriterTask(self.layer, tmp, options)
+
+        task.writeComplete.connect(self.onSuccess)
+        task.errorOccurred.connect(self.onFail)
+
+        QgsApplication.taskManager().addTask(task)
+        while not self.success and not self.fail:
+            QCoreApplication.processEvents()
+
+        self.assertTrue(self.success)
+        self.assertFalse(self.fail)
+
+    def testLayerRemovalBeforeRun(self):
+        """test behavior when layer is removed before task begins"""
+        self.layer = self.createLayer()
+        options = QgsVectorFileWriter.SaveVectorOptions()
+        tmp = create_temp_filename('fail.shp')
+        task = QgsVectorFileWriterTask(self.layer, tmp, options)
+
+        task.writeComplete.connect(self.onSuccess)
+        task.errorOccurred.connect(self.onFail)
+
+        # remove layer
+        self.layer = None
+
+        QgsApplication.taskManager().addTask(task)
+        while not self.success and not self.fail:
+            QCoreApplication.processEvents()
+
+        self.assertFalse(self.success)
+        self.assertTrue(self.fail)
+
+    def testNoLayer(self):
+        """test that failure (and not crash) occurs when no layer set"""
+
+        options = QgsVectorFileWriter.SaveVectorOptions()
+        tmp = create_temp_filename('fail.shp')
+        task = QgsVectorFileWriterTask(None, tmp, options)
+        task.writeComplete.connect(self.onSuccess)
+        task.errorOccurred.connect(self.onFail)
+
+        QgsApplication.taskManager().addTask(task)
+        while not self.success and not self.fail:
+            QCoreApplication.processEvents()
+
+        self.assertFalse(self.success)
+        self.assertTrue(self.fail)
+
+
+if __name__ == '__main__':
+    unittest.main()