1 //===- llvm/unittest/ADT/FunctionRefTest.cpp - function_ref unit tests ----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/ADT/STLExtras.h"
10 #include "gtest/gtest.h"
11
12 using namespace llvm;
13
14 namespace {
15
16 // Ensure that there is a default constructor and we can test for a null
17 // function_ref.
TEST(FunctionRefTest,Null)18 TEST(FunctionRefTest, Null) {
19 function_ref<int()> F;
20 EXPECT_FALSE(F);
21
22 auto L = [] { return 1; };
23 F = L;
24 EXPECT_TRUE(F);
25
26 F = {};
27 EXPECT_FALSE(F);
28 }
29
30 // Ensure that copies of a function_ref copy the underlying state rather than
31 // causing one function_ref to chain to the next.
TEST(FunctionRefTest,Copy)32 TEST(FunctionRefTest, Copy) {
33 auto A = [] { return 1; };
34 auto B = [] { return 2; };
35 function_ref<int()> X = A;
36 function_ref<int()> Y = X;
37 X = B;
38 EXPECT_EQ(1, Y());
39 }
40
TEST(FunctionRefTest,BadCopy)41 TEST(FunctionRefTest, BadCopy) {
42 auto A = [] { return 1; };
43 function_ref<int()> X;
44 function_ref<int()> Y = A;
45 function_ref<int()> Z = static_cast<const function_ref<int()> &&>(Y);
46 X = Z;
47 Y = nullptr;
48 ASSERT_EQ(1, X());
49 }
50
51 // Test that overloads on function_refs are resolved as expected.
returns(StringRef)52 std::string returns(StringRef) { return "not a function"; }
returns(function_ref<double ()> F)53 std::string returns(function_ref<double()> F) { return "number"; }
returns(function_ref<StringRef ()> F)54 std::string returns(function_ref<StringRef()> F) { return "string"; }
55
TEST(FunctionRefTest,SFINAE)56 TEST(FunctionRefTest, SFINAE) {
57 EXPECT_EQ("not a function", returns("boo!"));
58 EXPECT_EQ("number", returns([] { return 42; }));
59 EXPECT_EQ("string", returns([] { return "hello"; }));
60 }
61
62 } // namespace
63