tests/beman/exemplar/identity.test.cpp

	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

	#include <beman/exemplar/identity.hpp>

	#include <gtest/gtest.h>

	#include <algorithm>
	#include <functional>

	namespace exe = beman::exemplar;

	TEST(IdentityTest, call_identity_with_int) {
	for (int i = -100; i < 100; ++i) {
	EXPECT_EQ(i, exe::identity()(i));
	}
	}

	TEST(IdentityTest, call_identity_with_custom_type) {
	struct S {
	int i;
	};

	for (int i = -100; i < 100; ++i) {
	const S s{i};
	const S s_id = exe::identity()(s);
	EXPECT_EQ(s.i, s_id.i);
	}
	}

	TEST(IdentityTest, compare_std_vs_beman) {
	// Requires: std::identity support.
	#if defined(__cpp_lib_identity)
	std::identity std_id;
	exe::identity beman_id;
	for (int i = -100; i < 100; ++i) {
	EXPECT_EQ(std_id(i), beman_id(i));
	}
	#endif
	}

	TEST(IdentityTest, check_is_transparent) {
	// Requires: transparent operators support.
	#if defined(__cpp_lib_transparent_operators)

	exe::identity id;

	const auto container = {1, 2, 3, 4, 5};
	auto it = std::find(std::begin(container), std::end(container), 3);
	EXPECT_EQ(3, *it);
	auto it_with_id = std::find(std::begin(container), std::end(container), id(3));
	EXPECT_EQ(3, *it_with_id);

	EXPECT_EQ(it, it_with_id);
	#endif
	}

beman.exemplar