/*
* Copyright 2021 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
*
* http://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.
*/
// Testing utilities for working with absl::Status and absl::StatusOr.
//
// Defines the following utilities:
//
// =================
// DPF_EXPECT_OK(s)
//
// DPF_ASSERT_OK(s)
// =================
// Convenience macros for `EXPECT_THAT(s, IsOk())`, where `s` is either
// a `Status` or a `StatusOr<T>`.
//
// There are no EXPECT_NOT_OK/ASSERT_NOT_OK macros since they would not
// provide much value (when they fail, they would just print the OK status
// which conveys no more information than `EXPECT_FALSE(s.ok())`. You can
// of course use `EXPECT_THAT(s, Not(IsOk()))` if you prefer _THAT style.
//
// If you want to check for particular errors, better alternatives are:
// EXPECT_THAT(s, StatusIs(expected_error));
// EXPECT_THAT(s, StatusIs(_, HasSubstr("expected error")));
//
// ===============
// IsOkAndHolds(m)
// ===============
//
// This gMock matcher matches a StatusOr<T> value whose status is OK
// and whose inner value matches matcher m. Example:
//
// using ::testing::MatchesRegex;
// using distributed_point_functions::IsOkAndHolds;
// ...
// absl::StatusOr<string> maybe_name = ...;
// EXPECT_THAT(maybe_name, IsOkAndHolds(MatchesRegex("John .*")));
//
// ===============================
// StatusIs(status_code_matcher,
// error_message_matcher)
// ===============================
//
// This gMock matcher matches a Status or StatusOr<T> value if all of the
// following are true:
//
// - the status' error_code() matches status_code_matcher, and
// - the status' error_message() matches error_message_matcher.
//
// Example:
//
// enum FooErrorCode {
// ...
// kServerError
// };
//
// using ::testing::HasSubstr;
// using ::testing::MatchesRegex;
// using ::testing::Ne;
// using ::testing::_;
// using distributed_point_functions::StatusIs;
// absl::StatusOr<string> GetName(int id);
// ...
//
// // The status code must be kServerError; the error message can be
// // anything.
// EXPECT_THAT(GetName(42),
// StatusIs(kServerError, _));
// // The status code can be anything; the error message must match the
// // regex.
// EXPECT_THAT(GetName(43),
// StatusIs(_, MatchesRegex("server.*time-out")));
//
// // The status code should not be kServerError; the error message can be
// // anything with "client" in it.
// EXPECT_CALL(mock_env, HandleStatus(
// StatusIs(Ne(kServerError), HasSubstr("client"))));
//
// ===============================
// StatusIs(status_code_matcher)
// ===============================
//
// This is a shorthand for
// StatusIs(status_code_matcher,
// testing::_)
// In other words, it's like the two-argument StatusIs(), except that it
// ignores error message.
//
// ===============
// IsOk()
// ===============
//
// Matches an absl::Status or absl::StatusOr<T> value whose status value is
// absl::StatusCode::kOk. Equivalent to 'StatusIs(absl::StatusCode::kOk)'.
// Example:
// using distributed_point_functions::IsOk;
// ...
// absl::StatusOr<string> maybe_name = ...;
// EXPECT_THAT(maybe_name, IsOk());
// Status s = ...;
// EXPECT_THAT(s, IsOk());
//
#ifndef DISTRIBUTED_POINT_FUNCTIONS_DPF_UTIL_STATUS_MATCHERS_H_
#define DISTRIBUTED_POINT_FUNCTIONS_DPF_UTIL_STATUS_MATCHERS_H_
#include <ostream>
#include <string>
#include <type_traits>
#include <utility>
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "dpf/status_macros.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
namespace distributed_point_functions {
namespace dpf_internal {
inline const absl::Status& GetStatus(const absl::Status& status) {
return status;
}
template <typename T>
inline const absl::Status& GetStatus(const absl::StatusOr<T>& status) {
return status.status();
}
////////////////////////////////////////////////////////////
// Implementation of IsOkAndHolds().
// Monomorphic implementation of matcher IsOkAndHolds(m). StatusOrType is a
// reference to StatusOr<T>.
template <typename StatusOrType>
class IsOkAndHoldsMatcherImpl
: public ::testing::MatcherInterface<StatusOrType> {
public:
typedef
typename std::remove_reference<StatusOrType>::type::value_type value_type;
template <typename InnerMatcher>
explicit IsOkAndHoldsMatcherImpl(InnerMatcher&& inner_matcher)
: inner_matcher_(::testing::SafeMatcherCast<const value_type&>(
std::forward<InnerMatcher>(inner_matcher))) {}
void DescribeTo(std::ostream* os) const override {
*os << "is OK and has a value that ";
inner_matcher_.DescribeTo(os);
}
void DescribeNegationTo(std::ostream* os) const override {
*os << "isn't OK or has a value that ";
inner_matcher_.DescribeNegationTo(os);
}
bool MatchAndExplain(
StatusOrType actual_value,
::testing::MatchResultListener* result_listener) const override {
if (!actual_value.ok()) {
*result_listener << "which has status " << actual_value.status();
return false;
}
::testing::StringMatchResultListener inner_listener;
const bool matches =
inner_matcher_.MatchAndExplain(*actual_value, &inner_listener);
const std::string inner_explanation = inner_listener.str();
if (!inner_explanation.empty()) {
*result_listener << "which contains value "
<< ::testing::PrintToString(*actual_value) << ", "
<< inner_explanation;
}
return matches;
}
private:
const ::testing::Matcher<const value_type&> inner_matcher_;
};
// Implements IsOkAndHolds(m) as a polymorphic matcher.
template <typename InnerMatcher>
class IsOkAndHoldsMatcher {
public:
explicit IsOkAndHoldsMatcher(InnerMatcher inner_matcher)
: inner_matcher_(std::move(inner_matcher)) {}
// Converts this polymorphic matcher to a monomorphic matcher of the
// given type. StatusOrType can be either StatusOr<T> or a
// reference to StatusOr<T>.
template <typename StatusOrType>
operator ::testing::Matcher<StatusOrType>() const { // NOLINT
return ::testing::Matcher<StatusOrType>(
new IsOkAndHoldsMatcherImpl<const StatusOrType&>(inner_matcher_));
}
private:
const InnerMatcher inner_matcher_;
};
////////////////////////////////////////////////////////////
// Implementation of StatusIs().
// StatusIs() is a polymorphic matcher. This class is the common
// implementation of it shared by all types T where StatusIs() can be
// used as a Matcher<T>.
class StatusIsMatcherCommonImpl {
public:
StatusIsMatcherCommonImpl(
::testing::Matcher<absl::StatusCode> code_matcher,
::testing::Matcher<const std::string&> message_matcher)
: code_matcher_(std::move(code_matcher)),
message_matcher_(std::move(message_matcher)) {}
void DescribeTo(std::ostream* os) const;
void DescribeNegationTo(std::ostream* os) const;
bool MatchAndExplain(const absl::Status& status,
::testing::MatchResultListener* result_listener) const;
private:
const ::testing::Matcher<absl::StatusCode> code_matcher_;
const ::testing::Matcher<const std::string&> message_matcher_;
};
// Monomorphic implementation of matcher StatusIs() for a given type
// T. T can be Status, StatusOr<>, or a reference to either of them.
template <typename T>
class MonoStatusIsMatcherImpl : public ::testing::MatcherInterface<T> {
public:
explicit MonoStatusIsMatcherImpl(StatusIsMatcherCommonImpl common_impl)
: common_impl_(std::move(common_impl)) {}
void DescribeTo(std::ostream* os) const override {
common_impl_.DescribeTo(os);
}
void DescribeNegationTo(std::ostream* os) const override {
common_impl_.DescribeNegationTo(os);
}
bool MatchAndExplain(
T actual_value,
::testing::MatchResultListener* result_listener) const override {
return common_impl_.MatchAndExplain(GetStatus(actual_value),
result_listener);
}
private:
StatusIsMatcherCommonImpl common_impl_;
};
// Implements StatusIs() as a polymorphic matcher.
class StatusIsMatcher {
public:
template <typename StatusCodeMatcher, typename StatusMessageMatcher>
StatusIsMatcher(StatusCodeMatcher&& code_matcher,
StatusMessageMatcher&& message_matcher)
: common_impl_(::testing::MatcherCast<absl::StatusCode>(
std::forward<StatusCodeMatcher>(code_matcher)),
::testing::MatcherCast<const std::string&>(
std::forward<StatusMessageMatcher>(message_matcher))) {
}
// Converts this polymorphic matcher to a monomorphic matcher of the
// given type. T can be StatusOr<>, Status, or a reference to
// either of them.
template <typename T>
operator ::testing::Matcher<T>() const { // NOLINT
return ::testing::Matcher<T>(
new MonoStatusIsMatcherImpl<const T&>(common_impl_));
}
private:
const StatusIsMatcherCommonImpl common_impl_;
};
// Monomorphic implementation of matcher IsOk() for a given type T.
// T can be Status, StatusOr<>, or a reference to either of them.
template <typename T>
class MonoIsOkMatcherImpl : public ::testing::MatcherInterface<T> {
public:
void DescribeTo(std::ostream* os) const override { *os << "is OK"; }
void DescribeNegationTo(std::ostream* os) const override {
*os << "is not OK";
}
bool MatchAndExplain(
T actual_value,
::testing::MatchResultListener* result_listener) const override {
if (!actual_value.ok()) {
*result_listener << "whose status is "
<< GetStatus(actual_value).message();
return false;
}
return true;
}
};
// Implements IsOk() as a polymorphic matcher.
class IsOkMatcher {
public:
template <typename T>
operator ::testing::Matcher<T>() const { // NOLINT
return ::testing::Matcher<T>(new MonoIsOkMatcherImpl<const T&>());
}
};
// Macros for testing the results of functions that return absl::Status or
// absl::StatusOr<T> (for any type T).
#define DPF_EXPECT_OK(expression) \
EXPECT_THAT(expression, distributed_point_functions::dpf_internal::IsOk())
#define DPF_ASSERT_OK(expression) \
ASSERT_THAT(expression, distributed_point_functions::dpf_internal::IsOk())
// Executes an expression that returns an absl::StatusOr, and assigns the
// contained variable to lhs if the error code is OK.
// If the Status is non-OK, generates a test failure and returns from the
// current function, which must have a void return type.
//
// Example: Declaring and initializing a new value
// DPF_ASSERT_OK_AND_ASSIGN(const ValueType& value, MaybeGetValue(arg));
//
// Example: Assigning to an existing value
// ValueType value;
// DPF_ASSERT_OK_AND_ASSIGN(value, MaybeGetValue(arg));
//
// The value assignment example would expand into something like:
// auto status_or_value = MaybeGetValue(arg);
// DPF_ASSERT_OK(status_or_value.status());
// value = std::move(status_or_value).ValueOrDie();
//
// WARNING: Like ASSIGN_OR_RETURN, DPF_ASSERT_OK_AND_ASSIGN expands into
// multiple statements; it cannot be used in a single statement (e.g. as the
// body of an if statement without {})!
#define DPF_ASSERT_OK_AND_ASSIGN(lhs, rexpr) \
DPF_ASSERT_OK_AND_ASSIGN_IMPL_( \
DPF_STATUS_MACROS_IMPL_CONCAT_(_status_or_value, __LINE__), lhs, rexpr)
#define DPF_ASSERT_OK_AND_ASSIGN_IMPL_(statusor, lhs, rexpr) \
auto statusor = (rexpr); \
DPF_ASSERT_OK(statusor); \
lhs = std::move(statusor).value();
// Returns a gMock matcher that matches a StatusOr<> whose status is
// OK and whose value matches the inner matcher.
template <typename InnerMatcher>
dpf_internal::IsOkAndHoldsMatcher<typename std::decay<InnerMatcher>::type>
IsOkAndHolds(InnerMatcher&& inner_matcher) {
return dpf_internal::IsOkAndHoldsMatcher<
typename std::decay<InnerMatcher>::type>(
std::forward<InnerMatcher>(inner_matcher));
}
// Returns a gMock matcher that matches a Status or StatusOr<> whose status code
// matches code_matcher, and whose error message matches message_matcher.
template <typename StatusCodeMatcher, typename StatusMessageMatcher>
dpf_internal::StatusIsMatcher StatusIs(StatusCodeMatcher&& code_matcher,
StatusMessageMatcher&& message_matcher) {
return dpf_internal::StatusIsMatcher(
std::forward<StatusCodeMatcher>(code_matcher),
std::forward<StatusMessageMatcher>(message_matcher));
}
// Returns a gMock matcher that matches a Status or StatusOr<> whose status code
// matches code_matcher.
template <typename StatusCodeMatcher>
dpf_internal::StatusIsMatcher StatusIs(StatusCodeMatcher&& code_matcher) {
return StatusIs(std::forward<StatusCodeMatcher>(code_matcher), ::testing::_);
}
// Returns a gMock matcher that matches a Status or StatusOr<> which is OK.
inline dpf_internal::IsOkMatcher IsOk() { return dpf_internal::IsOkMatcher(); }
} // namespace dpf_internal
} // namespace distributed_point_functions
#endif // DISTRIBUTED_POINT_FUNCTIONS_DPF_UTIL_STATUS_MATCHERS_H_
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