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() {
  40   return std::unique_ptr<int>(new int(3));
  41 }
  42
  43 TEST(ErrorOr, Types) {
  44   int x;
  45   ErrorOr<int&> a(x);
  46   *a = 42;
  47   EXPECT_EQ(42, x);
  48
  49   // Move only types.
  50   EXPECT_EQ(3, **t3());
  51 }
  52
  53 struct B {};
  54 struct D : B {};
  55
  56 TEST(ErrorOr, Covariant) {
  57   ErrorOr<B*> b(ErrorOr<D*>(nullptr));
  58   b = ErrorOr<D*>(nullptr);
  59
  60   ErrorOr<std::unique_ptr<B> > b1(ErrorOr<std::unique_ptr<D> >(nullptr));
  61   b1 = ErrorOr<std::unique_ptr<D> >(nullptr);
  62
  63   ErrorOr<std::unique_ptr<int>> b2(ErrorOr<int *>(nullptr));
  64   ErrorOr<int *> b3(nullptr);
  65   ErrorOr<std::unique_ptr<int>> b4(b3);
  66 }
  67
  68 TEST(ErrorOr, Comparison) {
  69   ErrorOr<int> x(errc::no_such_file_or_directory);
  70   EXPECT_EQ(x, errc::no_such_file_or_directory);
  71 }
  72
  73 TEST(ErrorOr, ImplicitConversion) {
  74   ErrorOr<std::string> x("string literal");
  75   EXPECT_TRUE(!!x);
  76 }
  77
  78 TEST(ErrorOr, ImplicitConversionCausesMove) {
  79   struct Source {};
  80   struct Destination {
  81     Destination(const Source&) {}
  82     Destination(Source&&) = delete;
  83   };
  84   Source s;
  85   ErrorOr<Destination> x = s;
  86   EXPECT_TRUE(!!x);
  87 }
  88
  89 TEST(ErrorOr, ImplicitConversionNoAmbiguity) {
  90   struct CastsToErrorCode {
  91     CastsToErrorCode() = default;
  92     CastsToErrorCode(std::error_code) {}
  93     operator std::error_code() { return errc::invalid_argument; }
  94   } casts_to_error_code;
  95   ErrorOr<CastsToErrorCode> x1(casts_to_error_code);
  96   ErrorOr<CastsToErrorCode> x2 = casts_to_error_code;
  97   ErrorOr<CastsToErrorCode> x3 = {casts_to_error_code};
  98   ErrorOr<CastsToErrorCode> x4{casts_to_error_code};
  99   ErrorOr<CastsToErrorCode> x5(errc::no_such_file_or_directory);
 100   ErrorOr<CastsToErrorCode> x6 = errc::no_such_file_or_directory;
 101   ErrorOr<CastsToErrorCode> x7 = {errc::no_such_file_or_directory};
 102   ErrorOr<CastsToErrorCode> x8{errc::no_such_file_or_directory};
 103   EXPECT_TRUE(!!x1);
 104   EXPECT_TRUE(!!x2);
 105   EXPECT_TRUE(!!x3);
 106   EXPECT_TRUE(!!x4);
 107   EXPECT_FALSE(x5);
 108   EXPECT_FALSE(x6);
 109   EXPECT_FALSE(x7);
 110   EXPECT_FALSE(x8);
 111 }
 112
 113 // ErrorOr<int*> x(nullptr);
 114 // ErrorOr<std::unique_ptr<int>> y = x; // invalid conversion
 115 static_assert(
 116     !std::is_convertible<const ErrorOr<int *> &,
 117                          ErrorOr<std::unique_ptr<int>>>::value,
 118     "do not invoke explicit ctors in implicit conversion from lvalue");
 119
 120 // ErrorOr<std::unique_ptr<int>> y = ErrorOr<int*>(nullptr); // invalid
 121 //                                                           // conversion
 122 static_assert(
 123     !std::is_convertible<ErrorOr<int *> &&,
 124                          ErrorOr<std::unique_ptr<int>>>::value,
 125     "do not invoke explicit ctors in implicit conversion from rvalue");
 126
 127 // ErrorOr<int*> x(nullptr);
 128 // ErrorOr<std::unique_ptr<int>> y;
 129 // y = x; // invalid conversion
 130 static_assert(!std::is_assignable<ErrorOr<std::unique_ptr<int>>&,
 131                                   const ErrorOr<int *> &>::value,
 132               "do not invoke explicit ctors in assignment");
 133
 134 // ErrorOr<std::unique_ptr<int>> x;
 135 // x = ErrorOr<int*>(nullptr); // invalid conversion
 136 static_assert(!std::is_assignable<ErrorOr<std::unique_ptr<int>>&,
 137                                   ErrorOr<int *> &&>::value,
 138               "do not invoke explicit ctors in assignment");
 139 } // end anon namespace