Add specific test for QgsMultiBandColorRenderer

The raster blend mode test, which uses QgsMultiBandColorRenderer
fails occasionally for no obvious reason. This additional test
is an attempt to narrow down whether the issue lies in
rendering multi band images or elsewhere.

tests/src/core/testqgsrasterlayer.cpp

@@ -35,6 +35,7 @@
 #include <qgsmaprenderer.h>
 #include <qgssinglebandgrayrenderer.h>
 #include <qgssinglebandpseudocolorrenderer.h>
+#include <qgsmultibandcolorrenderer.h>
 #include <qgsvectorcolorrampv2.h>
 #include <qgscptcityarchive.h>
 
@@ -49,10 +50,11 @@ class TestQgsRasterLayer : public QObject
     Q_OBJECT
   public:
     TestQgsRasterLayer()
-        : mpRasterLayer( 0 )
-        , mpLandsatRasterLayer( 0 )
-        , mpFloat32RasterLayer( 0 )
-        , mMapSettings( 0 )
+        : mpRasterLayer( nullptr )
+        , mpLandsatRasterLayer( nullptr )
+        , mpFloat32RasterLayer( nullptr )
+        , mPngRasterLayer( nullptr )
+        , mMapSettings( nullptr )
     {}
     ~TestQgsRasterLayer()
     {
@@ -79,6 +81,7 @@ class TestQgsRasterLayer : public QObject
     void buildExternalOverviews();
     void registry();
     void transparency();
+    void multiBandColorRenderer();
     void setRenderer();
   private:
     bool render( const QString& theFileName );
@@ -92,6 +95,7 @@ class TestQgsRasterLayer : public QObject
     QgsRasterLayer * mpRasterLayer;
     QgsRasterLayer * mpLandsatRasterLayer;
     QgsRasterLayer * mpFloat32RasterLayer;
+    QgsRasterLayer * mPngRasterLayer;
     QgsMapSettings * mMapSettings;
     QString mReport;
 };
@@ -101,7 +105,7 @@ class TestSignalReceiver : public QObject
     Q_OBJECT
 
   public:
-    TestSignalReceiver() : QObject( 0 ),
+    TestSignalReceiver() : QObject( nullptr ),
         rendererChanged( false )
     {}
     bool rendererChanged;
@@ -132,6 +136,7 @@ void TestQgsRasterLayer::initTestCase()
   QString myFileName = mTestDataDir + "tenbytenraster.asc";
   QString myLandsatFileName = mTestDataDir + "landsat.tif";
   QString myFloat32FileName = mTestDataDir + "/raster/band1_float32_noct_epsg4326.tif";
+  QString pngRasterFileName = mTestDataDir + "rgb256x256.png";
 
   QFileInfo myRasterFileInfo( myFileName );
   mpRasterLayer = new QgsRasterLayer( myRasterFileInfo.filePath(),
@@ -148,13 +153,16 @@ void TestQgsRasterLayer::initTestCase()
       myFloat32RasterFileInfo.completeBaseName() );
   qDebug() << "float32raster metadata: " << mpFloat32RasterLayer->dataProvider()->metadata();
 
+  QFileInfo pngRasterFileInfo( pngRasterFileName );
+  mPngRasterLayer = new QgsRasterLayer( pngRasterFileInfo.filePath(),
+                                        pngRasterFileInfo.completeBaseName() );
+
   // Register the layer with the registry
   QgsMapLayerRegistry::instance()->addMapLayers(
-    QList<QgsMapLayer *>() << mpRasterLayer );
-  QgsMapLayerRegistry::instance()->addMapLayers(
-    QList<QgsMapLayer *>() << mpLandsatRasterLayer );
-  QgsMapLayerRegistry::instance()->addMapLayers(
-    QList<QgsMapLayer *>() << mpFloat32RasterLayer );
+    QList<QgsMapLayer *>() << mpRasterLayer
+    << mpLandsatRasterLayer
+    << mpFloat32RasterLayer
+    << mPngRasterLayer );
 
   // add the test layer to the maprender
   mMapSettings->setLayers( QStringList() << mpRasterLayer->id() );
@@ -597,6 +605,15 @@ void TestQgsRasterLayer::transparency()
   QVERIFY( render( "raster_transparency" ) );
 }
 
+void TestQgsRasterLayer::multiBandColorRenderer()
+{
+  QgsMultiBandColorRenderer* rasterRenderer = new QgsMultiBandColorRenderer( mPngRasterLayer->dataProvider(), 1, 2, 3 );
+  mPngRasterLayer->setRenderer( rasterRenderer );
+  mMapSettings->setLayers( QStringList() << mPngRasterLayer->id() );
+  mMapSettings->setExtent( mPngRasterLayer->extent() );
+  QVERIFY( render( "raster_multibandrenderer" ) );
+}
+
 void TestQgsRasterLayer::setRenderer()
 {
   TestSignalReceiver receiver;