Port Truncate alg to new API

Author: nyalldawson

python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py

@@ -114,6 +114,7 @@
 from .SymmetricalDifference import SymmetricalDifference
 from .TextToFloat import TextToFloat
 from .Translate import Translate
+from .TruncateTable import TruncateTable
 from .Union import Union
 from .UniqueValues import UniqueValues
 from .VectorSplit import VectorSplit
@@ -165,7 +166,6 @@
 # from .TinInterpolation import TinInterpolation
 # from .ExtractSpecificNodes import ExtractSpecificNodes
 # from .RasterCalculator import RasterCalculator
-# from .TruncateTable import TruncateTable
 # from .Polygonize import Polygonize
 # from .ExecuteSQL import ExecuteSQL
 # from .FindProjection import FindProjection
@@ -202,10 +202,7 @@ def getAlgs(self):
         #         StatisticsByCategories(),
         #         RasterLayerStatistics(), PointsDisplacement(),
         #         PointsFromPolygons(),
-        #         PointsFromLines(), RandomPointsExtent(),
-        #         RandomPointsLayer(), RandomPointsPolygonsFixed(),
-        #         RandomPointsPolygonsVariable(),
-        #         RandomPointsAlongLines(), PointsToPaths(),
+        #         PointsFromLines(), PointsToPaths(),
         #         SetVectorStyle(), SetRasterStyle(),
         #          HypsometricCurves(),
         #         SplitWithLines(), CreateConstantRaster(),
@@ -219,9 +216,7 @@ def getAlgs(self):
         #         IdwInterpolation(), TinInterpolation(),
         #         ExtractSpecificNodes(),
         #         RasterCalculator(),
-        #         ShortestPathPointToPoint(), ShortestPathPointToLayer(),
-        #         ShortestPathLayerToPoint(), ServiceAreaFromPoint(),
-        #         ServiceAreaFromLayer(), TruncateTable(), Polygonize(),
+        #         Polygonize(),
         #          ExecuteSQL(), FindProjection(),
         #         TopoColor(), EliminateSelection()
         #         ]
@@ -299,6 +294,7 @@ def getAlgs(self):
                 SymmetricalDifference(),
                 TextToFloat(),
                 Translate(),
+                TruncateTable(),
                 Union(),
                 UniqueValues(),
                 VectorSplit(),

python/plugins/processing/algs/qgis/TruncateTable.py

@@ -25,13 +25,10 @@
 
 __revision__ = '$Format:%H$'
 
-from qgis.core import (QgsApplication,
-                       QgsFeatureSink,
-                       QgsProcessingUtils)
+from qgis.core import (QgsProcessingParameterVectorLayer,
+                       QgsProcessingOutputVectorLayer,
+                       QgsProcessingException)
 from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
-from processing.core.parameters import ParameterTable
-from processing.core.outputs import OutputVector
-from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
 
 
 class TruncateTable(QgisAlgorithm):
@@ -49,10 +46,9 @@ def __init__(self):
         super().__init__()
 
     def initAlgorithm(self, config=None):
-        self.addParameter(ParameterTable(self.INPUT,
-                                         self.tr('Input Layer')))
-        self.addOutput(OutputVector(self.OUTPUT,
-                                    self.tr('Truncated layer'), True))
+        self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT,
+                                                            self.tr('Input Layer')))
+        self.addOutput(QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr('Truncated layer')))
 
     def name(self):
         return 'truncatetable'
@@ -61,12 +57,11 @@ def displayName(self):
         return self.tr('Truncate table')
 
     def processAlgorithm(self, parameters, context, feedback):
-        file_name = self.getParameterValue(self.INPUT)
-        layer = QgsProcessingUtils.mapLayerFromString(file_name, context)
+        layer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
         provider = layer.dataProvider()
 
         if not provider.truncate():
-            raise GeoAlgorithmExecutionException(
+            raise QgsProcessingException(
                 self.tr('Could not truncate table.'))
 
-        self.setOutputValue(self.OUTPUT, file_name)
+        return {self.OUTPUT: layer.id()}

python/plugins/processing/tests/AlgorithmsTestBase.py

@@ -256,7 +256,7 @@ def check_results(self, results, context, params, expected):
                 expected_lyr = self.load_layer(id, expected_result)
                 if 'in_place_result' in expected_result:
                     result_lyr = QgsProcessingUtils.mapLayerFromString(self.in_place_layers[id], context)
-                    self.assertTrue(result_lyr, self.in_place_layers[id])
+                    self.assertTrue(result_lyr.isValid(), self.in_place_layers[id])
                 else:
                     try:
                         results[id]

python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

@@ -2261,18 +2261,18 @@ tests:
         type: vector
         in_place_result: true
 
-#  - algorithm: qgis:truncatetable
-#    name: Truncate table
-#    params:
-#      INPUT:
-#        name: custom/points.shp
-#        type: vector
-#        in_place: true
-#    results:
-#      INPUT:
-#        name: expected/truncated.shp
-#        type: vector
-#        in_place_result: true
+  - algorithm: qgis:truncatetable
+    name: Truncate table
+    params:
+      INPUT:
+        name: custom/points.shp
+        type: vector
+        in_place: true
+    results:
+      INPUT:
+        name: expected/truncated.shp
+        type: vector
+        in_place_result: true
 
   - algorithm: qgis:distancematrix
     name: Distance matrix (only tests for run, does not check result as rows are in random order)