Add test for precision conversion with decl_hdf5

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to
 ### For users
 
 #### Added
+* Add tests for HDF5 precision conversion
 
 #### Changed
 

plugins/decl_hdf5/tests/compatibility_tests/CMakeLists.txt

@@ -60,3 +60,7 @@ foreach(test_name ${ALL_TEST_NAMES})
         endforeach(read_prefix)
     endforeach(write_prefix)
 endforeach(test_name)
+
+add_executable(decl_hdf5_conversion_test decl_hdf5_precision_conversion_test.cxx)
+target_link_libraries(decl_hdf5_conversion_test ${HDF5_DEPS} PDI::PDI_C GTest::gmock GTest::gmock_main GTest::gtest GTest::gtest_main)
+gtest_discover_tests(decl_hdf5_conversion_test)

plugins/decl_hdf5/tests/compatibility_tests/decl_hdf5_precision_conversion_test.cxx

@@ -0,0 +1,147 @@
+/*******************************************************************************
+ * Copyright (C) 2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * * Neither the name of CEA nor the names of its contributors may be used to
+ *   endorse or promote products derived from this software without specific
+ *   prior written permission.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ ******************************************************************************/
+
+#include <filesystem>
+#include <ranges>
+
+#include <hdf5.h>
+
+#include <pdi/testing.h>
+
+class DeclHdf5: public ::PDI::PdiTest
+{};
+
+/* Precision conversion with decl_hdf5 
+ * data in double precision
+ * file dataset in double, float, and int
+ */
+TEST_F(DeclHdf5, PrecisionConversion)
+{
+	InitPdi(PC_parse_string(R"==(
+logging: trace
+metadata:
+  N: int
+data:
+  array: {type: array, size: [$N, $N], subtype: double}
+plugins:
+  decl_hdf5:   
+    - file: d2d_test.h5
+      datasets:
+        double_ds: {type: array, size: [$N, $N], subtype: double}
+      write:
+        array:
+          dataset: double_ds
+    - file: d2f_test.h5
+      datasets:
+        float_ds: {type: array, size: [$N, $N], subtype: float}
+      write:
+        array:
+          dataset: float_ds
+    - file: d2i_test.h5
+      datasets:
+        int_ds: {type: array, size: [$N, $N], subtype: int}
+      write:
+        array:
+          dataset: int_ds
+)=="));
+
+	EXPECT_FALSE(std::filesystem::exists("d2d_test.h5"));
+	EXPECT_FALSE(std::filesystem::exists("d2f_test.h5"));
+	EXPECT_FALSE(std::filesystem::exists("d2i_test.h5"));
+
+	static constexpr size_t const N = 100;
+	PDI_expose("N", &N, PDI_OUT);
+
+	auto const test_array = make_a<std::array<std::array<double, N>, N>>();
+	PDI_expose("array", test_array.data(), PDI_OUT);
+
+	EXPECT_TRUE(std::filesystem::exists("d2d_test.h5"));
+	EXPECT_TRUE(std::filesystem::exists("d2f_test.h5"));
+	EXPECT_TRUE(std::filesystem::exists("d2i_test.h5"));
+
+	// read double precision dataset and compare
+	hid_t file_id = H5Fopen("d2d_test.h5", H5F_ACC_RDONLY, H5P_DEFAULT);
+	hid_t dataset_id = H5Dopen2(file_id, "/double_ds", H5P_DEFAULT);
+	hid_t type_id = H5Dget_type(dataset_id);
+
+	EXPECT_TRUE(H5Tequal(type_id, H5T_IEEE_F64LE));
+	std::array<std::array<double, N>, N> read_double_array;
+
+	herr_t status = H5Dread(dataset_id, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, read_double_array.data());
+	ASSERT_GE(status, 0);
+
+	EXPECT_EQ(test_array, read_double_array);
+
+	H5Tclose(type_id);
+	H5Dclose(dataset_id);
+	H5Fclose(file_id);
+
+	// read simple precision dataset and compare
+	file_id = H5Fopen("d2f_test.h5", H5F_ACC_RDONLY, H5P_DEFAULT);
+	dataset_id = H5Dopen2(file_id, "/float_ds", H5P_DEFAULT);
+	type_id = H5Dget_type(dataset_id);
+
+	EXPECT_TRUE(H5Tequal(type_id, H5T_IEEE_F32LE));
+	std::array< std::array<float, N>, N > read_float_array;
+
+	status = H5Dread(dataset_id, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, H5P_DEFAULT, read_float_array.data());
+	ASSERT_GE(status, 0);
+
+#if defined(__clang__) && (__clang_major__ == 15)
+// Skipping the numerical comparaison because Clang 15 has known issues with ranges.
+#else
+	EXPECT_THAT(read_float_array, testing::ElementsAreArray(test_array | std::views::transform([](std::array<double, N> const & aref) {
+																return testing::Pointwise(testing::FloatEq(), aref);
+															})));
+#endif
+
+	H5Tclose(type_id);
+	H5Dclose(dataset_id);
+	H5Fclose(file_id);
+
+	// read integer dataset and compare
+	file_id = H5Fopen("d2i_test.h5", H5F_ACC_RDONLY, H5P_DEFAULT);
+	dataset_id = H5Dopen2(file_id, "/int_ds", H5P_DEFAULT);
+	type_id = H5Dget_type(dataset_id);
+
+	EXPECT_TRUE(H5Tequal(type_id, H5T_STD_I32LE));
+	std::array< std::array<int, N>, N > read_int_array;
+
+	status = H5Dread(dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, read_int_array.data());
+	ASSERT_GE(status, 0);
+
+#if defined(__clang__) && (__clang_major__ == 15)
+// Skipping the numerical comparaison because Clang 15 has known issues with ranges.
+#else
+	EXPECT_THAT(read_int_array, testing::ElementsAreArray(test_array | std::views::transform([](std::array<double, N> const & aref) {
+															  return testing::ElementsAreArray(aref | std::views::transform([](double const & ref) {
+																								   return static_cast<int>(ref);
+																							   }));
+														  })));
+#endif
+
+	H5Tclose(type_id);
+	H5Dclose(dataset_id);
+	H5Fclose(file_id);
+}