exception-test.c++

// Copyright (c) 2013, Kenton Varda <temporal@gmail.com>
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "exception.h"
#include "debug.h"
#include <gtest/gtest.h>

namespace kj {
namespace _ {  // private
namespace {

TEST(Exception, RunCatchingExceptions) {
  bool recovered = false;
  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
    KJ_FAIL_ASSERT("foo") {
      break;
    }
    recovered = true;
  });

#if KJ_NO_EXCEPTIONS
  EXPECT_TRUE(recovered);
#else
  EXPECT_FALSE(recovered);
#endif

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("foo", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }
}

class ThrowingDestructor: public UnwindDetector {
public:
  ~ThrowingDestructor() noexcept(false) {
    catchExceptionsIfUnwinding([]() {
      KJ_FAIL_ASSERT("bar") { break; }
    });
  }
};

TEST(Exception, UnwindDetector) {
  // If no other exception is happening, ThrowingDestructor's destructor throws one.
  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
    ThrowingDestructor t;
  });

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("bar", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }

  // If another exception is happening, ThrowingDestructor's destructor's exception is squelched.
  e = kj::runCatchingExceptions([&]() {
    ThrowingDestructor t;
    KJ_FAIL_ASSERT("baz") {
      break;
    }
  });

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("baz", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }
}

TEST(Exception, ExceptionCallbackMustBeOnStack) {
#if KJ_NO_EXCEPTIONS
  EXPECT_DEATH_IF_SUPPORTED(new ExceptionCallback, "must be allocated on the stack");
#else
  EXPECT_ANY_THROW(new ExceptionCallback);
#endif
}

#if !KJ_NO_EXCEPTIONS
TEST(Exception, ScopeSuccessFail) {
  bool success = false;
  bool failure = false;

  {
    KJ_ON_SCOPE_SUCCESS(success = true);
    KJ_ON_SCOPE_FAILURE(failure = true);

    EXPECT_FALSE(success);
    EXPECT_FALSE(failure);
  }

  EXPECT_TRUE(success);
  EXPECT_FALSE(failure);

  success = false;
  failure = false;

  try {
    KJ_ON_SCOPE_SUCCESS(success = true);
    KJ_ON_SCOPE_FAILURE(failure = true);

    EXPECT_FALSE(success);
    EXPECT_FALSE(failure);

    throw 1;
  } catch (int) {}

  EXPECT_FALSE(success);
  EXPECT_TRUE(failure);
}
#endif

}  // namespace
}  // namespace _ (private)
}  // namespace kj