llvm-project/llvm/unittests/ADT/FunctionRefTest.cpp

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//===- llvm/unittest/ADT/FunctionRefTest.cpp - function_ref unit tests ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/STLExtras.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
// Ensure that there is a default constructor and we can test for a null
// function_ref.
TEST(FunctionRefTest, Null) {
function_ref<int()> F;
EXPECT_FALSE(F);
auto L = [] { return 1; };
F = L;
EXPECT_TRUE(F);
F = {};
EXPECT_FALSE(F);
}
// Ensure that copies of a function_ref copy the underlying state rather than
// causing one function_ref to chain to the next.
TEST(FunctionRefTest, Copy) {
auto A = [] { return 1; };
auto B = [] { return 2; };
function_ref<int()> X = A;
function_ref<int()> Y = X;
X = B;
EXPECT_EQ(1, Y());
}
TEST(FunctionRefTest, BadCopy) {
auto A = [] { return 1; };
function_ref<int()> X;
function_ref<int()> Y = A;
function_ref<int()> Z = static_cast<const function_ref<int()> &&>(Y);
X = Z;
Y = nullptr;
ASSERT_EQ(1, X());
}
// Test that overloads on function_refs are resolved as expected.
std::string returns(StringRef) { return "not a function"; }
std::string returns(function_ref<double()> F) { return "number"; }
std::string returns(function_ref<StringRef()> F) { return "string"; }
TEST(FunctionRefTest, SFINAE) {
EXPECT_EQ("not a function", returns("boo!"));
EXPECT_EQ("number", returns([] { return 42; }));
EXPECT_EQ("string", returns([] { return "hello"; }));
}
} // namespace