llvm/unittests/Support/ErrorOrTest.cpp

   1 //===- unittests/ErrorOrTest.cpp - ErrorOr.h 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/Support/ErrorOr.h"
  10 #include "llvm/Support/Errc.h"
  11 #include "gtest/gtest.h"
  12 #include <memory>
  13
  14 using namespace llvm;
  15
  16 namespace {
  17
  18 ErrorOr<int> t1() { return 1; }
  19 ErrorOr<int> t2() { return errc::invalid_argument; }
  20
  21 TEST(ErrorOr, SimpleValue) {
  22   ErrorOr<int> a = t1();
  23   // FIXME: This is probably a bug in gtest. EXPECT_TRUE should expand to
  24   // include the !! to make it friendly to explicit bool operators.
  25   EXPECT_TRUE(!!a);
  26   EXPECT_EQ(1, *a);
  27
  28   ErrorOr<int> b = a;
  29   EXPECT_EQ(1, *b);
  30
  31   a = t2();
  32   EXPECT_FALSE(a);
  33   EXPECT_EQ(a.getError(), errc::invalid_argument);
  34 #ifdef EXPECT_DEBUG_DEATH
  35   EXPECT_DEBUG_DEATH(*a, "Cannot get value when an error exists");
  36 #endif
  37 }
  38
  39 ErrorOr<std::unique_ptr<int>> t3() { return std::make_unique<int>(3); }
  40
  41 TEST(ErrorOr, Types) {
  42   int x;
  43   ErrorOr<int&> a(x);
  44   *a = 42;
  45   EXPECT_EQ(42, x);
  46
  47   // Move only types.
  48   EXPECT_EQ(3, **t3());
  49 }
  50
  51 struct B {};
  52 struct D : B {};
  53
  54 TEST(ErrorOr, Covariant) {
  55   ErrorOr<B*> b(ErrorOr<D*>(nullptr));
  56   b = ErrorOr<D*>(nullptr);
  57
  58   ErrorOr<std::unique_ptr<B> > b1(ErrorOr<std::unique_ptr<D> >(nullptr));
  59   b1 = ErrorOr<std::unique_ptr<D> >(nullptr);
  60
  61   ErrorOr<std::unique_ptr<int>> b2(ErrorOr<int *>(nullptr));
  62   ErrorOr<int *> b3(nullptr);
  63   ErrorOr<std::unique_ptr<int>> b4(b3);
  64 }
  65
  66 TEST(ErrorOr, Comparison) {
  67   ErrorOr<int> x(errc::no_such_file_or_directory);
  68   EXPECT_EQ(x, errc::no_such_file_or_directory);
  69 }
  70
  71 TEST(ErrorOr, ImplicitConversion) {
  72   ErrorOr<std::string> x("string literal");
  73   EXPECT_TRUE(!!x);
  74 }
  75
  76 TEST(ErrorOr, ImplicitConversionCausesMove) {
  77   struct Source {};
  78   struct Destination {
  79     Destination(const Source&) {}
  80     Destination(Source&&) = delete;
  81   };
  82   Source s;
  83   ErrorOr<Destination> x = s;
  84   EXPECT_TRUE(!!x);
  85 }
  86
  87 TEST(ErrorOr, ImplicitConversionNoAmbiguity) {
  88   struct CastsToErrorCode {
  89     CastsToErrorCode() = default;
  90     CastsToErrorCode(std::error_code) {}
  91     operator std::error_code() { return errc::invalid_argument; }
  92   } casts_to_error_code;
  93   ErrorOr<CastsToErrorCode> x1(casts_to_error_code);
  94   ErrorOr<CastsToErrorCode> x2 = casts_to_error_code;
  95   ErrorOr<CastsToErrorCode> x3 = {casts_to_error_code};
  96   ErrorOr<CastsToErrorCode> x4{casts_to_error_code};
  97   ErrorOr<CastsToErrorCode> x5(errc::no_such_file_or_directory);
  98   ErrorOr<CastsToErrorCode> x6 = errc::no_such_file_or_directory;
  99   ErrorOr<CastsToErrorCode> x7 = {errc::no_such_file_or_directory};
 100   ErrorOr<CastsToErrorCode> x8{errc::no_such_file_or_directory};
 101   EXPECT_TRUE(!!x1);
 102   EXPECT_TRUE(!!x2);
 103   EXPECT_TRUE(!!x3);
 104   EXPECT_TRUE(!!x4);
 105   EXPECT_FALSE(x5);
 106   EXPECT_FALSE(x6);
 107   EXPECT_FALSE(x7);
 108   EXPECT_FALSE(x8);
 109 }
 110
 111 // ErrorOr<int*> x(nullptr);
 112 // ErrorOr<std::unique_ptr<int>> y = x; // invalid conversion
 113 static_assert(
 114     !std::is_convertible_v<const ErrorOr<int *> &,
 115                            ErrorOr<std::unique_ptr<int>>>,
 116     "do not invoke explicit ctors in implicit conversion from lvalue");
 117
 118 // ErrorOr<std::unique_ptr<int>> y = ErrorOr<int*>(nullptr); // invalid
 119 //                                                           // conversion
 120 static_assert(
 121     !std::is_convertible_v<ErrorOr<int *> &&, ErrorOr<std::unique_ptr<int>>>,
 122     "do not invoke explicit ctors in implicit conversion from rvalue");
 123
 124 // ErrorOr<int*> x(nullptr);
 125 // ErrorOr<std::unique_ptr<int>> y;
 126 // y = x; // invalid conversion
 127 static_assert(!std::is_assignable_v<ErrorOr<std::unique_ptr<int>> &,
 128                                     const ErrorOr<int *> &>,
 129               "do not invoke explicit ctors in assignment");
 130
 131 // ErrorOr<std::unique_ptr<int>> x;
 132 // x = ErrorOr<int*>(nullptr); // invalid conversion
 133 static_assert(
 134     !std::is_assignable_v<ErrorOr<std::unique_ptr<int>> &, ErrorOr<int *> &&>,
 135     "do not invoke explicit ctors in assignment");
 136 } // end anon namespace