Files
nearby/internal/platform/exception_test.cc
Janusz Sobczak 7a99b5e0a3 Specialize ExceptionOr<bool>
ExceptionOr<T>::ok() returns true if the value is set. This can be misleading
for boolean types.
ExceptionOr<bool> result = SomeFunction();
if (result.ok()) {
 if (result.result() {
  // Case 1: SomeFunction returned true
 } else {
  // Case 2: SomeFunction returned false
} else {
  // Case 3: SomeFunction returned an exception
}
It's easy to overlook case 2.
The specialized ExceptionOr<bool>::ok() returns false in Case 2, which allows
us to write:
if (result) {
 // SomeFunction returned true
} else {
 // SomeFunction returned false or an exception
 // result.GetException() can be used if we need to handle different exceptions
 // differenty
}

PiperOrigin-RevId: 544715641
2023-06-30 11:59:43 -07:00

140 lines
4.5 KiB
C++

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "internal/platform/exception.h"
#include <vector>
#include "gmock/gmock.h"
#include "protobuf-matchers/protocol-buffer-matchers.h"
#include "gtest/gtest.h"
#include "internal/platform/exception_test.nc.h"
namespace nearby {
TEST(ExceptionOr, Result_Copy_NonConst) {
ExceptionOr<std::vector<int>> exception_or_vector({1, 2, 3});
EXPECT_FALSE(exception_or_vector.result().empty());
// Expect a copy when not explicitly moving the result.
std::vector<int> copy = exception_or_vector.result();
EXPECT_FALSE(copy.empty());
EXPECT_FALSE(exception_or_vector.result().empty());
// Modifying |exception_or_vector| should not affect the copy.
exception_or_vector.result().clear();
EXPECT_FALSE(copy.empty());
}
TEST(ExceptionOr, Result_Copy_Const) {
const ExceptionOr<std::vector<int>> exception_or_vector({1, 2, 3});
EXPECT_FALSE(exception_or_vector.result().empty());
// Expect a copy when not explicitly moving the result.
const std::vector<int>& copy = exception_or_vector.result();
EXPECT_FALSE(copy.empty());
EXPECT_FALSE(exception_or_vector.result().empty());
}
TEST(ExceptionOr, Result_Reference_NonConst) {
ExceptionOr<std::vector<int>> exception_or_vector({1, 2, 3});
EXPECT_FALSE(exception_or_vector.result().empty());
// Getting a reference should not modify the source.
std::vector<int>& reference = exception_or_vector.result();
EXPECT_FALSE(reference.empty());
EXPECT_FALSE(exception_or_vector.result().empty());
// Modifying |exception_or_vector| should reflect in the reference.
exception_or_vector.result().clear();
EXPECT_TRUE(reference.empty());
}
TEST(ExceptionOr, Result_Reference_Const) {
const ExceptionOr<std::vector<int>> exception_or_vector({1, 2, 3});
EXPECT_FALSE(exception_or_vector.result().empty());
// Getting a reference should not modify the source.
const std::vector<int>& reference = exception_or_vector.result();
EXPECT_FALSE(reference.empty());
EXPECT_FALSE(exception_or_vector.result().empty());
}
TEST(ExceptionOr, Result_Move_NonConst) {
ExceptionOr<std::vector<int>> exception_or_vector({1, 2, 3});
EXPECT_FALSE(exception_or_vector.result().empty());
// Moving the result should clear the source.
std::vector<int> moved = std::move(exception_or_vector).result();
EXPECT_FALSE(moved.empty());
}
TEST(ExceptionOr, Result_Move_Const) {
const ExceptionOr<std::vector<int>> exception_or_vector({1, 2, 3});
EXPECT_FALSE(exception_or_vector.result().empty());
// Moving const rvalue reference will result in a copy.
std::vector<int> moved = std::move(exception_or_vector).result();
EXPECT_FALSE(moved.empty());
}
TEST(ExceptionOr, ExplicitConversionWorks) {
class A {
public:
A() = default;
};
class B {
public:
B() = default;
explicit B(A) {}
};
ExceptionOr<A> a(A{});
ExceptionOr<B> b(a);
EXPECT_TRUE(a.ok());
EXPECT_TRUE(b.ok());
}
TEST(ExceptionOr, ExplicitConversionFailsToCompile) {
class A {
public:
A() = default;
};
class B {
public:
B() = default;
};
ExceptionOr<A> a(A{});
EXPECT_NON_COMPILE("no matching constructor", { ExceptionOr<B> b(a); });
}
TEST(ExceptionOr, BoolType) {
EXPECT_TRUE(ExceptionOr<bool>(true));
EXPECT_TRUE(ExceptionOr<bool>(true).GetResult());
EXPECT_TRUE(ExceptionOr<bool>(true).result());
EXPECT_TRUE(ExceptionOr<bool>(true).ok());
EXPECT_EQ(ExceptionOr<bool>(true).exception(), Exception::kSuccess);
EXPECT_TRUE(ExceptionOr<bool>(Exception::kSuccess));
EXPECT_FALSE(ExceptionOr<bool>(false));
EXPECT_FALSE(ExceptionOr<bool>(false).GetResult());
EXPECT_FALSE(ExceptionOr<bool>(false).result());
EXPECT_FALSE(ExceptionOr<bool>(false).ok());
EXPECT_EQ(ExceptionOr<bool>(false).exception(), Exception::kFailed);
EXPECT_FALSE(ExceptionOr<bool>());
EXPECT_FALSE(ExceptionOr<bool>(Exception::kInterrupted));
EXPECT_EQ(ExceptionOr<bool>(Exception::kInterrupted).exception(),
Exception::kInterrupted);
}
} // namespace nearby