Merge pull request #2904 from AmatanHead:throw-matchers
PiperOrigin-RevId: 327294137
diff --git a/googlemock/include/gmock/gmock-matchers.h b/googlemock/include/gmock/gmock-matchers.h
index 0bc9b36..a897611 100644
--- a/googlemock/include/gmock/gmock-matchers.h
+++ b/googlemock/include/gmock/gmock-matchers.h
@@ -4725,6 +4725,175 @@
internal::variant_matcher::VariantMatcher<T>(matcher));
}
+#if GTEST_HAS_EXCEPTIONS
+
+// Anything inside the `internal` namespace is internal to the implementation
+// and must not be used in user code!
+namespace internal {
+
+class WithWhatMatcherImpl {
+ public:
+ WithWhatMatcherImpl(Matcher<std::string> matcher)
+ : matcher_(std::move(matcher)) {}
+
+ void DescribeTo(std::ostream* os) const {
+ *os << "contains .what() that ";
+ matcher_.DescribeTo(os);
+ }
+
+ void DescribeNegationTo(std::ostream* os) const {
+ *os << "contains .what() that does not ";
+ matcher_.DescribeTo(os);
+ }
+
+ template <typename Err>
+ bool MatchAndExplain(const Err& err, MatchResultListener* listener) const {
+ *listener << "which contains .what() that ";
+ return matcher_.MatchAndExplain(err.what(), listener);
+ }
+
+ private:
+ const Matcher<std::string> matcher_;
+};
+
+inline PolymorphicMatcher<WithWhatMatcherImpl> WithWhat(
+ Matcher<std::string> m) {
+ return MakePolymorphicMatcher(WithWhatMatcherImpl(std::move(m)));
+}
+
+template <typename Err>
+class ExceptionMatcherImpl {
+ class NeverThrown {
+ public:
+ const char* what() const noexcept {
+ return "this exception should never be thrown";
+ }
+ };
+
+ // If the matchee raises an exception of a wrong type, we'd like to
+ // catch it and print its message and type. To do that, we add an additional
+ // catch clause:
+ //
+ // try { ... }
+ // catch (const Err&) { /* an expected exception */ }
+ // catch (const std::exception&) { /* exception of a wrong type */ }
+ //
+ // However, if the `Err` itself is `std::exception`, we'd end up with two
+ // identical `catch` clauses:
+ //
+ // try { ... }
+ // catch (const std::exception&) { /* an expected exception */ }
+ // catch (const std::exception&) { /* exception of a wrong type */ }
+ //
+ // This can cause a warning or an error in some compilers. To resolve
+ // the issue, we use a fake error type whenever `Err` is `std::exception`:
+ //
+ // try { ... }
+ // catch (const std::exception&) { /* an expected exception */ }
+ // catch (const NeverThrown&) { /* exception of a wrong type */ }
+ using DefaultExceptionType = typename std::conditional<
+ std::is_same<typename std::remove_cv<
+ typename std::remove_reference<Err>::type>::type,
+ std::exception>::value,
+ const NeverThrown&, const std::exception&>::type;
+
+ public:
+ ExceptionMatcherImpl(Matcher<const Err&> matcher)
+ : matcher_(std::move(matcher)) {}
+
+ void DescribeTo(std::ostream* os) const {
+ *os << "throws an exception which is a " << GetTypeName<Err>();
+ *os << " which ";
+ matcher_.DescribeTo(os);
+ }
+
+ void DescribeNegationTo(std::ostream* os) const {
+ *os << "throws an exception which is not a " << GetTypeName<Err>();
+ *os << " which ";
+ matcher_.DescribeNegationTo(os);
+ }
+
+ template <typename T>
+ bool MatchAndExplain(T&& x, MatchResultListener* listener) const {
+ try {
+ (void)(std::forward<T>(x)());
+ } catch (const Err& err) {
+ *listener << "throws an exception which is a " << GetTypeName<Err>();
+ *listener << " ";
+ return matcher_.MatchAndExplain(err, listener);
+ } catch (DefaultExceptionType err) {
+#if GTEST_HAS_RTTI
+ *listener << "throws an exception of type " << GetTypeName(typeid(err));
+ *listener << " ";
+#else
+ *listener << "throws an std::exception-derived type ";
+#endif
+ *listener << "with description \"" << err.what() << "\"";
+ return false;
+ } catch (...) {
+ *listener << "throws an exception of an unknown type";
+ return false;
+ }
+
+ *listener << "does not throw any exception";
+ return false;
+ }
+
+ private:
+ const Matcher<const Err&> matcher_;
+};
+
+} // namespace internal
+
+// Throws()
+// Throws(exceptionMatcher)
+// ThrowsMessage(messageMatcher)
+//
+// This matcher accepts a callable and verifies that when invoked, it throws
+// an exception with the given type and properties.
+//
+// Examples:
+//
+// EXPECT_THAT(
+// []() { throw std::runtime_error("message"); },
+// Throws<std::runtime_error>());
+//
+// EXPECT_THAT(
+// []() { throw std::runtime_error("message"); },
+// ThrowsMessage<std::runtime_error>(HasSubstr("message")));
+//
+// EXPECT_THAT(
+// []() { throw std::runtime_error("message"); },
+// Throws<std::runtime_error>(
+// Property(&std::runtime_error::what, HasSubstr("message"))));
+
+template <typename Err>
+PolymorphicMatcher<internal::ExceptionMatcherImpl<Err>> Throws() {
+ return MakePolymorphicMatcher(
+ internal::ExceptionMatcherImpl<Err>(A<const Err&>()));
+}
+
+template <typename Err, typename ExceptionMatcher>
+PolymorphicMatcher<internal::ExceptionMatcherImpl<Err>> Throws(
+ const ExceptionMatcher& exception_matcher) {
+ // Using matcher cast allows users to pass a matcher of a more broad type.
+ // For example user may want to pass Matcher<std::exception>
+ // to Throws<std::runtime_error>, or Matcher<int64> to Throws<int32>.
+ return MakePolymorphicMatcher(internal::ExceptionMatcherImpl<Err>(
+ SafeMatcherCast<const Err&>(exception_matcher)));
+}
+
+template <typename Err, typename MessageMatcher>
+PolymorphicMatcher<internal::ExceptionMatcherImpl<Err>> ThrowsMessage(
+ MessageMatcher&& message_matcher) {
+ static_assert(std::is_base_of<std::exception, Err>::value,
+ "expected an std::exception-derived type");
+ return Throws<Err>(internal::WithWhat(
+ MatcherCast<std::string>(std::forward<MessageMatcher>(message_matcher))));
+}
+
+#endif // GTEST_HAS_EXCEPTIONS
+
// These macros allow using matchers to check values in Google Test
// tests. ASSERT_THAT(value, matcher) and EXPECT_THAT(value, matcher)
// succeed if and only if the value matches the matcher. If the assertion
diff --git a/googlemock/test/gmock-matchers_test.cc b/googlemock/test/gmock-matchers_test.cc
index 015bb09..1cba156 100644
--- a/googlemock/test/gmock-matchers_test.cc
+++ b/googlemock/test/gmock-matchers_test.cc
@@ -8117,6 +8117,190 @@
EXPECT_THAT(p, Not(UniquePointee(2)));
}
+#if GTEST_HAS_EXCEPTIONS
+
+// std::function<void()> is used below for compatibility with older copies of
+// GCC. Normally, a raw lambda is all that is needed.
+
+// Test that examples from documentation compile
+TEST(ThrowsTest, Examples) {
+ EXPECT_THAT(
+ std::function<void()>([]() { throw std::runtime_error("message"); }),
+ Throws<std::runtime_error>());
+
+ EXPECT_THAT(
+ std::function<void()>([]() { throw std::runtime_error("message"); }),
+ ThrowsMessage<std::runtime_error>(HasSubstr("message")));
+}
+
+TEST(ThrowsTest, DoesNotGenerateDuplicateCatchClauseWarning) {
+ EXPECT_THAT(std::function<void()>([]() { throw std::exception(); }),
+ Throws<std::exception>());
+}
+
+TEST(ThrowsTest, CallableExecutedExactlyOnce) {
+ size_t a = 0;
+
+ EXPECT_THAT(std::function<void()>([&a]() {
+ a++;
+ throw 10;
+ }),
+ Throws<int>());
+ EXPECT_EQ(a, 1u);
+
+ EXPECT_THAT(std::function<void()>([&a]() {
+ a++;
+ throw std::runtime_error("message");
+ }),
+ Throws<std::runtime_error>());
+ EXPECT_EQ(a, 2u);
+
+ EXPECT_THAT(std::function<void()>([&a]() {
+ a++;
+ throw std::runtime_error("message");
+ }),
+ ThrowsMessage<std::runtime_error>(HasSubstr("message")));
+ EXPECT_EQ(a, 3u);
+
+ EXPECT_THAT(std::function<void()>([&a]() {
+ a++;
+ throw std::runtime_error("message");
+ }),
+ Throws<std::runtime_error>(
+ Property(&std::runtime_error::what, HasSubstr("message"))));
+ EXPECT_EQ(a, 4u);
+}
+
+TEST(ThrowsTest, Describe) {
+ Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+ std::stringstream ss;
+ matcher.DescribeTo(&ss);
+ auto explanation = ss.str();
+ EXPECT_THAT(explanation, HasSubstr("std::runtime_error"));
+}
+
+TEST(ThrowsTest, Success) {
+ Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+ StringMatchResultListener listener;
+ EXPECT_TRUE(matcher.MatchAndExplain(
+ []() { throw std::runtime_error("error message"); }, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("std::runtime_error"));
+}
+
+TEST(ThrowsTest, FailWrongType) {
+ Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain(
+ []() { throw std::logic_error("error message"); }, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("std::logic_error"));
+ EXPECT_THAT(listener.str(), HasSubstr("\"error message\""));
+}
+
+TEST(ThrowsTest, FailWrongTypeNonStd) {
+ Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain([]() { throw 10; }, &listener));
+ EXPECT_THAT(listener.str(),
+ HasSubstr("throws an exception of an unknown type"));
+}
+
+TEST(ThrowsTest, FailNoThrow) {
+ Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain([]() { (void)0; }, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("does not throw any exception"));
+}
+
+class ThrowsPredicateTest
+ : public TestWithParam<Matcher<std::function<void()>>> {};
+
+TEST_P(ThrowsPredicateTest, Describe) {
+ Matcher<std::function<void()>> matcher = GetParam();
+ std::stringstream ss;
+ matcher.DescribeTo(&ss);
+ auto explanation = ss.str();
+ EXPECT_THAT(explanation, HasSubstr("std::runtime_error"));
+ EXPECT_THAT(explanation, HasSubstr("error message"));
+}
+
+TEST_P(ThrowsPredicateTest, Success) {
+ Matcher<std::function<void()>> matcher = GetParam();
+ StringMatchResultListener listener;
+ EXPECT_TRUE(matcher.MatchAndExplain(
+ []() { throw std::runtime_error("error message"); }, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("std::runtime_error"));
+}
+
+TEST_P(ThrowsPredicateTest, FailWrongType) {
+ Matcher<std::function<void()>> matcher = GetParam();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain(
+ []() { throw std::logic_error("error message"); }, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("std::logic_error"));
+ EXPECT_THAT(listener.str(), HasSubstr("\"error message\""));
+}
+
+TEST_P(ThrowsPredicateTest, FailWrongTypeNonStd) {
+ Matcher<std::function<void()>> matcher = GetParam();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain([]() { throw 10; }, &listener));
+ EXPECT_THAT(listener.str(),
+ HasSubstr("throws an exception of an unknown type"));
+}
+
+TEST_P(ThrowsPredicateTest, FailWrongMessage) {
+ Matcher<std::function<void()>> matcher = GetParam();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain(
+ []() { throw std::runtime_error("wrong message"); }, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("std::runtime_error"));
+ EXPECT_THAT(listener.str(), Not(HasSubstr("wrong message")));
+}
+
+TEST_P(ThrowsPredicateTest, FailNoThrow) {
+ Matcher<std::function<void()>> matcher = GetParam();
+ StringMatchResultListener listener;
+ EXPECT_FALSE(matcher.MatchAndExplain([]() {}, &listener));
+ EXPECT_THAT(listener.str(), HasSubstr("does not throw any exception"));
+}
+
+INSTANTIATE_TEST_SUITE_P(
+ AllMessagePredicates, ThrowsPredicateTest,
+ Values(Matcher<std::function<void()>>(
+ ThrowsMessage<std::runtime_error>(HasSubstr("error message")))));
+
+// Tests that Throws<E1>(Matcher<E2>{}) compiles even when E2 != const E1&.
+TEST(ThrowsPredicateCompilesTest, ExceptionMatcherAcceptsBroadType) {
+ {
+ Matcher<std::function<void()>> matcher =
+ ThrowsMessage<std::runtime_error>(HasSubstr("error message"));
+ EXPECT_TRUE(
+ matcher.Matches([]() { throw std::runtime_error("error message"); }));
+ EXPECT_FALSE(
+ matcher.Matches([]() { throw std::runtime_error("wrong message"); }));
+ }
+
+ {
+ Matcher<uint64_t> inner = Eq(10);
+ Matcher<std::function<void()>> matcher = Throws<uint32_t>(inner);
+ EXPECT_TRUE(matcher.Matches([]() { throw(uint32_t) 10; }));
+ EXPECT_FALSE(matcher.Matches([]() { throw(uint32_t) 11; }));
+ }
+}
+
+// Tests that ThrowsMessage("message") is equivalent
+// to ThrowsMessage(Eq<std::string>("message")).
+TEST(ThrowsPredicateCompilesTest, MessageMatcherAcceptsNonMatcher) {
+ Matcher<std::function<void()>> matcher =
+ ThrowsMessage<std::runtime_error>("error message");
+ EXPECT_TRUE(
+ matcher.Matches([]() { throw std::runtime_error("error message"); }));
+ EXPECT_FALSE(matcher.Matches(
+ []() { throw std::runtime_error("wrong error message"); }));
+}
+
+#endif // GTEST_HAS_EXCEPTIONS
+
} // namespace
} // namespace gmock_matchers_test
} // namespace testing
