Move test code: strings and empty arrays.

doc/developer_guide.md

@@ -195,6 +195,9 @@ Write-read cycles for scalar values should be implemented in
 Unit-tests related to checking that `DataType` API, go in
 `tests/unit/tests_high_data_type.cpp`.
 
+#### Empty Arrays
+Check related to empty arrays to in `tests/unit/test_empty_arrays.cpp`.
+
 #### Selections
 Anything selection related goes in `tests/unit/test_high_five_selection.cpp`.
 This includes things like `ElementSet` and `HyperSlab`.
@@ -204,7 +207,7 @@ Regular write-read cycles for strings are performed along with the other types,
 see above. This should cover compatibility of `std::string` with all
 containers. However, additional testing is required, e.g. character set,
 padding, fixed vs. variable length. These all go in
-`tests/unit/test_high_five_string.cpp`.
+`tests/unit/test_string.cpp`.
 
 #### Specific Tests For Optional Containers
 If containers, e.g. `Eigen::Matrix` require special checks those go in files

tests/unit/CMakeLists.txt

@@ -6,7 +6,7 @@ if(MSVC)
 endif()
 
 ## Base tests
-foreach(test_name tests_high_five_base tests_high_five_multi_dims tests_high_five_easy test_all_types test_high_five_selection tests_high_five_data_type test_legacy)
+foreach(test_name tests_high_five_base tests_high_five_multi_dims tests_high_five_easy test_all_types test_high_five_selection tests_high_five_data_type test_empty_arrays test_legacy test_string)
   add_executable(${test_name} "${test_name}.cpp")
   target_link_libraries(${test_name} HighFive HighFiveWarnings HighFiveFlags Catch2::Catch2WithMain)
   target_link_libraries(${test_name} HighFiveOptionalDependencies)

tests/unit/test_empty_arrays.cpp

@@ -0,0 +1,248 @@
+/*
+ *  Copyright (c), 2017-2024, Blue Brain Project - EPFL
+ *
+ *  Distributed under the Boost Software License, Version 1.0.
+ *    (See accompanying file LICENSE_1_0.txt or copy at
+ *          http://www.boost.org/LICENSE_1_0.txt)
+ *
+ */
+#include <string>
+#include <vector>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/catch_template_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_vector.hpp>
+
+#include <highfive/highfive.hpp>
+#include "tests_high_five.hpp"
+#include "create_traits.hpp"
+
+#ifdef HIGHFIVE_TEST_BOOST
+#include <highfive/boost.hpp>
+#endif
+
+#ifdef HIGHFIVE_TEST_EIGEN
+#include <highfive/eigen.hpp>
+#endif
+
+#ifdef HIGHFIVE_TEST_SPAN
+#include <highfive/span.hpp>
+#endif
+
+using namespace HighFive;
+using Catch::Matchers::Equals;
+
+
+template <int n_dim>
+struct CreateEmptyVector;
+
+template <>
+struct CreateEmptyVector<1> {
+    using container_type = std::vector<int>;
+
+    static container_type create(const std::vector<size_t>& dims) {
+        return container_type(dims[0], 2);
+    }
+};
+
+template <int n_dim>
+struct CreateEmptyVector {
+    using container_type = std::vector<typename CreateEmptyVector<n_dim - 1>::container_type>;
+
+    static container_type create(const std::vector<size_t>& dims) {
+        auto subdims = std::vector<size_t>(dims.begin() + 1, dims.end());
+        return container_type(dims[0], CreateEmptyVector<n_dim - 1>::create(subdims));
+    }
+};
+
+#ifdef HIGHFIVE_TEST_BOOST
+template <int n_dim>
+struct CreateEmptyBoostMultiArray {
+    using container_type = boost::multi_array<int, static_cast<long unsigned>(n_dim)>;
+
+    static container_type create(const std::vector<size_t>& dims) {
+        auto container = container_type(dims);
+
+        auto raw_data = std::vector<int>(compute_total_size(dims));
+        container.assign(raw_data.begin(), raw_data.end());
+
+        return container;
+    }
+};
+#endif
+
+
+#ifdef HIGHFIVE_TEST_EIGEN
+struct CreateEmptyEigenVector {
+    using container_type = Eigen::VectorXi;
+
+    static container_type create(const std::vector<size_t>& dims) {
+        return container_type::Constant(int(dims[0]), 2);
+    }
+};
+
+struct CreateEmptyEigenMatrix {
+    using container_type = Eigen::MatrixXi;
+
+    static container_type create(const std::vector<size_t>& dims) {
+        return container_type::Constant(int(dims[0]), int(dims[1]), 2);
+    }
+};
+#endif
+
+template <class Container>
+void check_empty_dimensions(const Container& container, const std::vector<size_t>& expected_dims) {
+    auto deduced_dims = details::inspector<Container>::getDimensions(container);
+
+    REQUIRE(expected_dims.size() == deduced_dims.size());
+
+    // The dims after hitting the first `0` are finicky. We allow those to be deduced as either `1`
+    // or what the original dims said. The `1` allows broadcasting, the "same as original" enables
+    // statically sized objects, which conceptually have dims, even if there's no object.
+    bool allow_one = false;
+    for (size_t i = 0; i < expected_dims.size(); ++i) {
+        REQUIRE(((expected_dims[i] == deduced_dims[i]) || (allow_one && (deduced_dims[i] == 1ul))));
+
+        if (expected_dims[i] == 0) {
+            allow_one = true;
+        }
+    }
+}
+
+template <class CreateContainer>
+void check_empty_dimensions(const std::vector<size_t>& dims) {
+    auto input_data = CreateContainer::create(dims);
+    check_empty_dimensions(input_data, dims);
+}
+
+template <class ReadWriteInterface, class CreateContainer>
+void check_empty_read_write_cycle(const std::vector<size_t>& dims) {
+    using container_type = typename CreateContainer::container_type;
+
+    const std::string file_name("h5_empty_attr.h5");
+    const std::string dataset_name("dset");
+    File file(file_name, File::Truncate);
+
+    auto input_data = CreateContainer::create(dims);
+    ReadWriteInterface::create(file, dataset_name, input_data);
+
+    SECTION("read; one-dimensional vector (empty)") {
+        auto output_data = CreateEmptyVector<1>::create({0ul});
+
+        ReadWriteInterface::get(file, dataset_name).reshapeMemSpace({0ul}).read(output_data);
+        check_empty_dimensions(output_data, {0ul});
+    }
+
+    SECTION("read; pre-allocated (empty)") {
+        auto output_data = CreateContainer::create(dims);
+        ReadWriteInterface::get(file, dataset_name).reshapeMemSpace(dims).read(output_data);
+
+        check_empty_dimensions(output_data, dims);
+    }
+
+    SECTION("read; pre-allocated (oversized)") {
+        auto oversize_dims = std::vector<size_t>(dims.size(), 2ul);
+        auto output_data = CreateContainer::create(oversize_dims);
+        ReadWriteInterface::get(file, dataset_name).reshapeMemSpace(dims).read(output_data);
+
+        check_empty_dimensions(output_data, dims);
+    }
+
+    SECTION("read; auto-allocated") {
+        auto output_data = ReadWriteInterface::get(file, dataset_name)
+                               .reshapeMemSpace(dims)
+                               .template read<container_type>();
+        check_empty_dimensions(output_data, dims);
+    }
+}
+
+template <class CreateContainer>
+void check_empty_dataset(const std::vector<size_t>& dims) {
+    check_empty_read_write_cycle<testing::DataSetCreateTraits, CreateContainer>(dims);
+}
+
+template <class CreateContainer>
+void check_empty_attribute(const std::vector<size_t>& dims) {
+    check_empty_read_write_cycle<testing::AttributeCreateTraits, CreateContainer>(dims);
+}
+
+template <class CreateContainer>
+void check_empty_everything(const std::vector<size_t>& dims) {
+    SECTION("Empty dimensions") {
+        check_empty_dimensions<CreateContainer>(dims);
+    }
+
+    SECTION("Empty datasets") {
+        check_empty_dataset<CreateContainer>(dims);
+    }
+
+    SECTION("Empty attribute") {
+        check_empty_attribute<CreateContainer>(dims);
+    }
+}
+
+#ifdef HIGHFIVE_TEST_EIGEN
+template <int ndim>
+void check_empty_eigen(const std::vector<size_t>&) {}
+
+template <>
+void check_empty_eigen<1>(const std::vector<size_t>& dims) {
+    SECTION("Eigen::Vector") {
+        check_empty_everything<CreateEmptyEigenVector>({dims[0], 1ul});
+    }
+}
+
+template <>
+void check_empty_eigen<2>(const std::vector<size_t>& dims) {
+    SECTION("Eigen::Matrix") {
+        check_empty_everything<CreateEmptyEigenMatrix>(dims);
+    }
+}
+#endif
+
+template <int ndim>
+void check_empty(const std::vector<size_t>& dims) {
+    REQUIRE(dims.size() == ndim);
+
+    SECTION("std::vector") {
+        check_empty_everything<CreateEmptyVector<ndim>>(dims);
+    }
+
+#ifdef HIGHFIVE_TEST_BOOST
+    SECTION("boost::multi_array") {
+        check_empty_everything<CreateEmptyBoostMultiArray<ndim>>(dims);
+    }
+#endif
+
+#ifdef HIGHFIVE_TEST_EIGEN
+    check_empty_eigen<ndim>(dims);
+#endif
+}
+
+TEST_CASE("Empty arrays") {
+    SECTION("one-dimensional") {
+        check_empty<1>({0ul});
+    }
+
+    SECTION("two-dimensional") {
+        std::vector<std::vector<size_t>> testcases{{0ul, 1ul}, {1ul, 0ul}};
+
+        for (const auto& dims: testcases) {
+            SECTION(details::format_vector(dims)) {
+                check_empty<2>(dims);
+            }
+        }
+    }
+
+    SECTION("three-dimensional") {
+        std::vector<std::vector<size_t>> testcases{{0ul, 1ul, 1ul},
+                                                   {1ul, 1ul, 0ul},
+                                                   {1ul, 0ul, 1ul}};
+
+        for (const auto& dims: testcases) {
+            SECTION(details::format_vector(dims)) {
+                check_empty<3>(dims);
+            }
+        }
+    }
+}