ENH: Increase coverage for itk::RoundImageFilter

Increase coverage for `itk::RoundImageFilter`:
- Exercise basic object methods using the
  `ITK_EXERCISE_BASIC_OBJECT_METHODS` macro.
- Test the output of the filter.

Modules/Filtering/ImageIntensity/test/CMakeLists.txt

@@ -77,6 +77,7 @@ itkLessTest.cxx
 itkClampImageFilterTest.cxx
 itkNthElementPixelAccessorTest2.cxx
 itkMagnitudeAndPhaseToComplexImageFilterTest.cxx
+itkRoundImageFilterTest.cxx
 )
 
 if (NOT ITK_LEGACY_REMOVE)
@@ -344,7 +345,8 @@ itk_add_test(NAME itkMagnitudeAndPhaseToComplexImageFilterTest
       DATA{Input/itkBrainSliceComplexMagnitude.mha}
       DATA{Input/itkBrainSliceComplexPhase.mha}
       ${ITK_TEST_OUTPUT_DIR}/itkMagnitudeAndPhaseToComplexImageFilterTest.mha)
-
+itk_add_test(NAME itkRoundImageFilterTest
+      COMMAND ITKImageIntensityTestDriver itkRoundImageFilterTest)
 
 set(ITKImageIntensityGTests
   itkBitwiseOpsFunctorsTest.cxx

Modules/Filtering/ImageIntensity/test/itkRoundImageFilterTest.cxx

@@ -0,0 +1,80 @@
+/*=========================================================================
+ *
+ *  Copyright NumFOCUS
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *         https://www.apache.org/licenses/LICENSE-2.0.txt
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *=========================================================================*/
+
+#include "itkImageRegionIterator.h"
+#include "itkMath.h"
+#include "itkRandomImageSource.h"
+#include "itkRoundImageFilter.h"
+#include "itkTestingMacros.h"
+
+
+int
+itkRoundImageFilterTest(int, char *[])
+{
+
+  constexpr unsigned int Dimension = 2;
+
+  using InputPixelType = float;
+  using OutputPixelType = int;
+
+  using InputImageType = itk::Image<InputPixelType, Dimension>;
+  using OutputImageType = itk::Image<OutputPixelType, Dimension>;
+
+  using ImageSourceType = itk::RandomImageSource<InputImageType>;
+
+  using FilterType = itk::RoundImageFilter<InputImageType, OutputImageType>;
+  auto roundImageFilter = FilterType::New();
+
+  ITK_EXERCISE_BASIC_OBJECT_METHODS(roundImageFilter, RoundImageFilter, UnaryGeneratorImageFilter);
+
+
+  // Create a random image
+  auto randomImageSource = ImageSourceType::New();
+
+  const InputImageType::SizeType size{ { 10, 10 } };
+  randomImageSource->SetSize(size);
+
+  randomImageSource->SetMin(0.0);
+  randomImageSource->SetMax(10.0);
+
+  randomImageSource->SetNumberOfWorkUnits(1);
+
+  roundImageFilter->SetInput(randomImageSource->GetOutput());
+
+  ITK_TRY_EXPECT_NO_EXCEPTION(roundImageFilter->Update());
+
+  itk::ImageRegionIterator<InputImageType>  it1(randomImageSource->GetOutput(),
+                                               randomImageSource->GetOutput()->GetLargestPossibleRegion());
+  itk::ImageRegionIterator<OutputImageType> it2(roundImageFilter->GetOutput(),
+                                                roundImageFilter->GetOutput()->GetLargestPossibleRegion());
+
+  it1.GoToBegin();
+  it2.GoToBegin();
+
+  while (!it1.IsAtEnd() || !it2.IsAtEnd())
+  {
+    ITK_TEST_EXPECT_EQUAL(itk::Math::Round<OutputImageType::ValueType>(it1.Get()), it2.Get());
+
+    ++it1;
+    ++it2;
+  }
+
+
+  std::cout << "Test finished." << std::endl;
+  return EXIT_SUCCESS;
+}