GEOS precision tests

tests/src/core/CMakeLists.txt

@@ -123,6 +123,7 @@ ADD_QGIS_TEST(fieldtest testqgsfield.cpp)
 ADD_QGIS_TEST(filewritertest testqgsvectorfilewriter.cpp)
 ADD_QGIS_TEST(fontutils testqgsfontutils.cpp)
 ADD_QGIS_TEST(geometryimporttest testqgsgeometryimport.cpp)
+ADD_QGIS_TEST(geostest testqgsgeos.cpp)
 ADD_QGIS_TEST(geometrytest testqgsgeometry.cpp)
 ADD_QGIS_TEST(geometryutilstest testqgsgeometryutils.cpp)
 ADD_QGIS_TEST(gradienttest testqgsgradients.cpp )

tests/src/core/testqgsgeos.cpp

@@ -0,0 +1,107 @@
+/***************************************************************************
+     TestQgsGeos.cpp
+     --------------------------------------
+    Date                 : 03 Sept 2014
+    Copyright            : (C) 2014 by Marco Hugentobler
+    Email                : marco@sourcepole.ch
+ ***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsapplication.h"
+#include "geos_c.h"
+#include "geosextra/geos_c_extra.h"
+
+
+#include <QtTest/QtTest>
+#include <QObject>
+
+class TestQgsGeos: public QObject
+{
+    Q_OBJECT
+
+  private slots:
+
+    void initTestCase();
+
+    void lineIntersection_data();
+    void lineIntersection();
+};
+
+void TestQgsGeos::initTestCase()
+{
+  initGEOS( 0, 0 );
+}
+
+void TestQgsGeos::lineIntersection_data()
+{
+  QTest::addColumn<QString>( "wkt_inputA" );
+  QTest::addColumn<QString>( "wkt_inputB" );
+  QTest::addColumn<QString>( "precision" );
+  QTest::addColumn<QString>( "wkt_result" );
+
+  QTest::newRow( "floating" ) << "LINESTRING(0 -10, 2 10)"
+  << "LINESTRING(2 -10, 0 10)"
+  << "double"
+  << "POINT (1.0000000000000000 0.0000000000000000)";
+  QTest::newRow( "fixed" ) << "LINESTRING(0 -10, 2 10)"
+  << "LINESTRING(2 -10, 0 10)"
+  << "0.5"
+  << "POINT (2.0000000000000000 0.0000000000000000)";
+}
+
+void TestQgsGeos::lineIntersection()
+{
+  QFETCH( QString, wkt_inputA );
+  QFETCH( QString, wkt_inputB );
+  QFETCH( QString, precision );
+  QFETCH( QString, wkt_result );
+
+  GEOSGeometry* geomA = GEOSGeomFromWKT( wkt_inputA.toLocal8Bit().data() );
+  GEOSGeometry* geomB = GEOSGeomFromWKT( wkt_inputB.toLocal8Bit().data() );
+
+  GEOSPrecisionModel* model;
+  if ( precision == "double" )
+  {
+    model = GEOSPrecisionModel_create( GEOS_PRECISION_FLOATING );
+  }
+  else if ( precision == "single" )
+  {
+    model = GEOSPrecisionModel_create( GEOS_PRECISION_FLOATING_SINGLE );
+  }
+  else
+  {
+    bool ok = false;
+    double scale = precision.toDouble( &ok );
+    Q_ASSERT( ok );
+    model = GEOSPrecisionModel_createFixed( scale );
+  }
+
+  GEOSGeometryPrecisionReducer* reducer = GEOSGeometryPrecisionReducer_create( model );
+
+  GEOSGeometry* geomAr = GEOSGeometryPrecisionReducer_reduce( reducer, geomA );
+  GEOSGeometry* geomBr = GEOSGeometryPrecisionReducer_reduce( reducer, geomB );
+
+  GEOSGeometry* inter = GEOSIntersection( geomAr, geomBr );
+
+  char* resultwkt = GEOSGeomToWKT( inter );
+
+  QCOMPARE( QString( resultwkt ), wkt_result );
+
+  free( resultwkt );
+  GEOSGeom_destroy( geomAr );
+  GEOSGeom_destroy( geomBr );
+  GEOSGeom_destroy( geomA );
+  GEOSGeom_destroy( geomB );
+  GEOSGeometryPrecisionReducer_destroy( reducer );
+  GEOSPrecisionModel_destroy( model );
+}
+
+
+QTEST_MAIN( TestQgsGeos )
+#include "testqgsgeos.moc"