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/*=========================================================================
*
* 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.
*
*=========================================================================*/
#ifndef itkRangeGTestUtilities_h
#define itkRangeGTestUtilities_h
#include <gtest/gtest.h> // For EXPECT_EQ.
#include <utility> // For move.
#include <iterator> // For begin and end.
namespace itk
{
// Utilities for GoogleTest unit tests of iterator ranges.
// Note: This class is only for internal (testing) purposes.
// It is not part of the public API of ITK.
class RangeGTestUtilities
{
public:
template <typename TRange>
static void
ExpectBeginIsEndWhenRangeIsDefaultConstructed()
{
TRange defaultConstructedRange;
EXPECT_EQ(std::begin(defaultConstructedRange), std::end(defaultConstructedRange));
}
template <typename TRange>
static void
ExpectZeroSizeWhenRangeIsDefaultConstructed()
{
TRange defaultConstructedRange;
EXPECT_EQ(defaultConstructedRange.size(), 0);
}
template <typename TRange>
static void
ExpectRangeIsEmptyWhenDefaultConstructed()
{
TRange defaultConstructedRange;
EXPECT_TRUE(defaultConstructedRange.empty());
}
template <typename TRange>
static void
ExpectCopyConstructedRangeHasSameIteratorsAsOriginal(const TRange & originalRange)
{
const TRange copyConstructedRange(originalRange);
ExpectRangesHaveEqualBeginAndEnd(copyConstructedRange, originalRange);
}
template <typename TRange>
static void
ExpectCopyAssignedRangeHasSameIteratorsAsOriginal(const TRange & originalRange)
{
TRange copyAssignedRange;
copyAssignedRange = originalRange;
ExpectRangesHaveEqualBeginAndEnd(copyAssignedRange, originalRange);
}
template <typename TRange>
static void
ExpectMoveConstructedRangeHasSameIteratorsAsOriginalBeforeMove(TRange && originalRange)
{
const TRange originalRangeBeforeMove = originalRange;
TRange moveConstructedRange(std::move(originalRange));
ExpectRangesHaveEqualBeginAndEnd(moveConstructedRange, originalRangeBeforeMove);
}
template <typename TRange>
static void
ExpectMoveAssignedRangeHasSameIteratorsAsOriginalBeforeMove(TRange && originalRange)
{
const TRange originalRangeBeforeMove = originalRange;
TRange moveAssignedRange;
moveAssignedRange = std::move(originalRange);
ExpectRangesHaveEqualBeginAndEnd(moveAssignedRange, originalRangeBeforeMove);
}
template <typename TRange>
static void
ExpectIteratorIsDefaultConstructible()
{
using IteratorType = typename TRange::iterator;
IteratorType defaultConstructedIterator{};
// Test that a default-constructed iterator behaves according to C++ proposal
// N3644, "Null Forward Iterators" by Alan Talbot, which is accepted with
// C++14: "value-initialized iterators may be compared and shall compare
// equal to other value-initialized iterators of the same type."
// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3644.pdf
ExpectIteratorEqualsItself(defaultConstructedIterator);
EXPECT_EQ(defaultConstructedIterator, IteratorType());
}
// Checks the `constexpr` member functions begin() and end() of a container like FixedArray, Index, Offset and Size.
template <typename TContainer>
static constexpr bool
CheckConstexprBeginAndEndOfContainer()
{
using ConstContainerType = const TContainer;
using ValueType = std::remove_reference_t<decltype(*(TContainer().begin()))>;
static_assert(std::is_same_v<decltype(*(TContainer().begin())), ValueType &>,
"For a non-const container, begin() should return a non-const reference");
static_assert(std::is_same_v<decltype(*(ConstContainerType().begin())), const ValueType &>,
"For a const container, begin() should return a const reference");
static_assert(std::is_same_v<decltype(*(TContainer().cbegin())), const ValueType &> &&
std::is_same_v<decltype(*(ConstContainerType().cbegin())), const ValueType &>,
"For any container, cbegin() should return a const reference");
static_assert(std::is_same_v<decltype(*(TContainer().end())), ValueType &>,
"For a non-const container, end() should return a non-const reference");
static_assert(std::is_same_v<decltype(*(ConstContainerType().end())), const ValueType &>,
"For a const container, end() should return a const reference");
static_assert(std::is_same_v<decltype(*(TContainer().cend())), const ValueType &> &&
std::is_same_v<decltype(*(ConstContainerType().cend())), const ValueType &>,
"For any container, cend() should return a const reference");
constexpr TContainer container{};
static_assert(container.cbegin() == container.begin(), "cbegin() should return the same iterator as begin().");
static_assert(container.cend() == container.end(), "cend() should return the same iterator as end().");
// Just return true to ease calling this function inside a static_assert.
return true;
}
// Checks that each element of the specified range is zero.
template <typename TRange>
static void
ExpectEachElementIsZero(const TRange & range)
{
for (const auto & element : range)
{
EXPECT_EQ(element, 0);
}
}
private:
template <typename TRange>
static void
ExpectRangesHaveEqualBeginAndEnd(const TRange & range1, const TRange & range2)
{
EXPECT_EQ(std::begin(range1), std::begin(range2));
EXPECT_EQ(std::end(range1), std::end(range2));
}
template <typename TIterator>
static void
ExpectIteratorEqualsItself(const TIterator & it)
{
static_assert(!std::is_pointer_v<TIterator>,
"There should be a specific `ExpectIteratorEqualsItself` overload for a pointer as argument");
// Checks the (typically) user-defined `operator==` and `operator!=` of TIterator.
EXPECT_TRUE(it == it);
EXPECT_FALSE(it != it);
}
template <typename TValue>
static void
ExpectIteratorEqualsItself(TValue *)
{
// Overload for the use of a pointer type as iterator. Intentionally does "nothing", as a pointer always
// equals itself, by definition. Aims to avoid "warning: self-comparison always evaluates to false/true
// [-Wtautological-compare]", as produced by clang 13.0.1 on Ubuntu 20.04.
}
};
} // end namespace itk
#endif
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