[relations] Add method to manager to retrieve relations by name

Also
- Begin unit tests for QgsRelationManager
- Make project optional when constructing QgsRelationManager

python/core/qgsrelationmanager.sip

@@ -7,7 +7,11 @@ class QgsRelationManager : QObject
 #include "qgsrelationmanager.h"
 %End
   public:
-    explicit QgsRelationManager( QgsProject *project );
+
+    /** Constructor for QgsRelationManager.
+     * @param project associated project (used to notify project of changes)
+     */
+    explicit QgsRelationManager( QgsProject *project = nullptr );
 
     /**
      * Will set the specified relations and remove any relation currently set.
@@ -50,9 +54,18 @@ class QgsRelationManager : QObject
      * @param id The id to search for
      *
      * @return A relation. Invalid if not found.
+     * @see relationsByName()
      */
     QgsRelation relation( const QString& id ) const;
 
+    /** Returns a list of relations with matching names.
+     * @param name relation name to search for. Searching is case insensitive.
+     * @returns a list of matching relations
+     * @note added in QGIS 2.16
+     * @see relation()
+     */
+    QList<QgsRelation> relationsByName( const QString& name ) const;
+
     /**
      * Remove any relation managed by this class.
      */

src/core/qgsrelationmanager.cpp

@@ -52,7 +52,8 @@ void QgsRelationManager::addRelation( const QgsRelation& relation )
 
   mRelations.insert( relation.id(), relation );
 
-  mProject->setDirty( true );
+  if ( mProject )
+    mProject->setDirty( true );
   emit changed();
 }
 
@@ -73,6 +74,19 @@ QgsRelation QgsRelationManager::relation( const QString& id ) const
   return mRelations.value( id );
 }
 
+QList<QgsRelation> QgsRelationManager::relationsByName( const QString& name ) const
+{
+  QList<QgsRelation> relations;
+
+  Q_FOREACH ( const QgsRelation& rel, mRelations )
+  {
+    if ( QString::compare( rel.name(), name, Qt::CaseInsensitive ) == 0 )
+      relations << rel;
+  }
+
+  return relations;
+}
+
 void QgsRelationManager::clear()
 {
   mRelations.clear();

src/core/qgsrelationmanager.h

@@ -34,7 +34,11 @@ class CORE_EXPORT QgsRelationManager : public QObject
     Q_OBJECT
 
   public:
-    explicit QgsRelationManager( QgsProject *project );
+
+    /** Constructor for QgsRelationManager.
+     * @param project associated project (used to notify project of changes)
+     */
+    explicit QgsRelationManager( QgsProject *project = nullptr );
 
     /**
      * Will set the specified relations and remove any relation currently set.
@@ -77,9 +81,18 @@ class CORE_EXPORT QgsRelationManager : public QObject
      * @param id The id to search for
      *
      * @return A relation. Invalid if not found.
+     * @see relationsByName()
      */
     QgsRelation relation( const QString& id ) const;
 
+    /** Returns a list of relations with matching names.
+     * @param name relation name to search for. Searching is case insensitive.
+     * @returns a list of matching relations
+     * @note added in QGIS 2.16
+     * @see relation()
+     */
+    QList<QgsRelation> relationsByName( const QString& name ) const;
+
     /**
      * Remove any relation managed by this class.
      */

tests/src/python/CMakeLists.txt

@@ -62,6 +62,7 @@ ADD_PYTHON_TEST(PyQgsRasterFileWriter test_qgsrasterfilewriter.py)
 ADD_PYTHON_TEST(PyQgsRasterLayer test_qgsrasterlayer.py)
 ADD_PYTHON_TEST(PyQgsRectangle test_qgsrectangle.py)
 ADD_PYTHON_TEST(PyQgsRelation test_qgsrelation.py)
+ADD_PYTHON_TEST(PyQgsRelationManager test_qgsrelationmanager.py)
 ADD_PYTHON_TEST(PyQgsRulebasedRenderer test_qgsrulebasedrenderer.py)
 ADD_PYTHON_TEST(PyQgsSingleSymbolRenderer test_qgssinglesymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsShapefileProvider test_provider_shapefile.py)

tests/src/python/test_qgsrelationmanager.py

@@ -0,0 +1,158 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsRelationManager.
+
+.. 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__ = '17/05/2016'
+__copyright__ = 'Copyright 2016, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+import qgis  # NOQA
+
+from qgis.core import (QgsVectorLayer,
+                       QgsRelation,
+                       QgsRelationManager,
+                       QgsMapLayerRegistry
+                       )
+from qgis.testing import start_app, unittest
+
+start_app()
+
+
+def createReferencingLayer():
+    layer = QgsVectorLayer("Point?field=fldtxt:string&field=foreignkey:integer",
+                           "referencinglayer", "memory")
+    return layer
+
+
+def createReferencedLayer():
+    layer = QgsVectorLayer(
+        "Point?field=x:string&field=y:integer&field=z:integer",
+        "referencedlayer", "memory")
+    return layer
+
+
+class TestQgsRelationManager(unittest.TestCase):
+
+    def setUp(self):
+        self.referencedLayer = createReferencedLayer()
+        self.referencingLayer = createReferencingLayer()
+        QgsMapLayerRegistry.instance().addMapLayers([self.referencedLayer, self.referencingLayer])
+
+    def tearDown(self):
+        QgsMapLayerRegistry.instance().removeAllMapLayers()
+
+    def createRelation(self):
+        rel = QgsRelation()
+        rel.setReferencingLayer(self.referencingLayer.id())
+        rel.setReferencedLayer(self.referencedLayer.id())
+        rel.addFieldPair('foreignkey', 'y')
+        return rel
+
+    def test_addRelation(self):
+        """ test adding relations to a manager """
+        manager = QgsRelationManager()
+
+        relations = manager.relations()
+        self.assertEqual(len(relations), 0)
+
+        rel = self.createRelation()
+        rel.setRelationId('rel1')
+        rel.setRelationName('Relation Number One')
+        assert rel.isValid()
+
+        manager.addRelation(rel)
+
+        relations = manager.relations()
+        self.assertEqual(len(relations), 1)
+        self.assertEqual(relations['rel1'].id(), 'rel1')
+
+        rel = self.createRelation()
+        rel.setRelationId('rel2')
+        rel.setRelationName('Relation Number Two')
+        assert rel.isValid()
+
+        manager.addRelation(rel)
+
+        relations = manager.relations()
+        self.assertEqual(len(relations), 2)
+        ids = [r.id() for r in relations.values()]
+        self.assertEqual(set(ids), set(['rel1', 'rel2']))
+
+    def test_relationById(self):
+        """ test retrieving relation by id"""
+        manager = QgsRelationManager()
+
+        rel = manager.relation('does not exist')
+        self.assertFalse(rel.isValid())
+
+        # add two relations
+        rel = self.createRelation()
+        rel.setRelationId('rel1')
+        rel.setRelationName('Relation Number One')
+        assert rel.isValid()
+        manager.addRelation(rel)
+        rel = self.createRelation()
+        rel.setRelationId('rel2')
+        rel.setRelationName('Relation Number Two')
+        assert rel.isValid()
+        manager.addRelation(rel)
+
+        rel = manager.relation('does not exist')
+        self.assertFalse(rel.isValid())
+
+        rel = manager.relation('rel1')
+        self.assertEqual(rel.id(), 'rel1')
+
+        rel = manager.relation('rel2')
+        self.assertEqual(rel.id(), 'rel2')
+
+    def test_relationByName(self):
+        """ test retrieving relations by name"""
+        manager = QgsRelationManager()
+
+        rels = manager.relationsByName('does not exist')
+        self.assertEqual(rels, [])
+
+        # add some relations
+        rel = self.createRelation()
+        rel.setRelationId('rel1')
+        rel.setRelationName('my relation')
+        assert rel.isValid()
+        manager.addRelation(rel)
+        rel = self.createRelation()
+        rel.setRelationId('rel2')
+        rel.setRelationName('dupe name')
+        assert rel.isValid()
+        manager.addRelation(rel)
+        rel = self.createRelation()
+        rel.setRelationId('rel3')
+        rel.setRelationName('dupe name')
+        assert rel.isValid()
+        manager.addRelation(rel)
+
+        rels = manager.relationsByName('does not exist')
+        self.assertEqual(rels, [])
+
+        rels = manager.relationsByName('my relation')
+        ids = [r.id() for r in rels]
+        self.assertEqual(set(ids), set(['rel1']))
+
+        # case insensitive
+        rels = manager.relationsByName('My RelAtion')
+        ids = [r.id() for r in rels]
+        self.assertEqual(set(ids), set(['rel1']))
+
+        # multiple results
+        rels = manager.relationsByName('dupe name')
+        ids = [r.id() for r in rels]
+        self.assertEqual(set(ids), set(['rel2', 'rel3']))
+
+
+if __name__ == '__main__':
+    unittest.main()