Make compiled tests more stable

we do not want to ignore AttributeErrors for those

tests/src/python/providertestbase.py

@@ -52,6 +52,11 @@ def uncompiledFilters(self):
         cannot be compiled """
         return set()
 
+    def enableCompiler(self):
+        """By default there is no expression compiling available, needs to be overridden in subclass"""
+        print('Provider does not support compiling')
+        return False
+
     def partiallyCompiledFilters(self):
         """ Individual derived provider tests should override this to return a list of expressions which
         should be partially compiled """
@@ -141,14 +146,11 @@ def testGetFeaturesUncompiled(self):
             self.runPolyGetFeatureTests(self.poly_provider)
 
     def testGetFeaturesExp(self):
-        try:
-            self.enableCompiler()
+        if self.enableCompiler():
             self.compiled = True
             self.runGetFeatureTests(self.source)
             if hasattr(self, 'poly_provider'):
                 self.runPolyGetFeatureTests(self.poly_provider)
-        except AttributeError:
-            print('Provider does not support compiling')
 
     def testSubsetString(self):
         if not self.source.supportsSubsetString():
@@ -232,11 +234,8 @@ def testOrderBy(self):
         self.runOrderByTests()
 
     def testOrderByCompiled(self):
-        try:
-            self.enableCompiler()
+        if self.enableCompiler():
             self.runOrderByTests()
-        except AttributeError:
-            print('Provider does not support compiling')
 
     def runOrderByTests(self):
         FeatureSourceTestCase.runOrderByTests(self)

tests/src/python/test_provider_db2.py

@@ -58,6 +58,7 @@ def getSubsetString(self):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)

tests/src/python/test_provider_mssql.py

@@ -52,6 +52,7 @@ def tearDownClass(cls):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)

tests/src/python/test_provider_oracle.py

@@ -85,6 +85,7 @@ def getEditableLayer(self):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)

tests/src/python/test_provider_postgres.py

@@ -104,6 +104,7 @@ def getEditableLayer(self):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)
@@ -1125,6 +1126,7 @@ def tearDownClass(cls):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)

tests/src/python/test_provider_shapefile.py

@@ -93,6 +93,7 @@ def getEditableLayer(self):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)

tests/src/python/test_provider_spatialite.py

@@ -260,6 +260,7 @@ def tearDown(self):
 
     def enableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', True)
+        return True
 
     def disableCompiler(self):
         QgsSettings().setValue('/qgis/compileExpressions', False)