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- // (C) Copyright 2015 Boost.Test team.
- // Distributed under the Boost Software License, Version 1.0.
- // (See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- // See http://www.boost.org/libs/test for the library home page.
- //[example_code
- #define BOOST_TEST_MODULE example
- #include <boost/test/included/unit_test.hpp>
- #include <stdexcept>
- #include <fstream>
- //! Computes the histogram of the words in a text file
- class FileWordHistogram
- {
- public:
- //!@throw std::exception if the file does not exist
- FileWordHistogram(std::string filename) : is_processed(false), fileStream_(filename) {
- if(!fileStream_.is_open()) throw std::runtime_error("Cannot open the file");
- }
- //! @returns true on success, false otherwise
- bool process() {
- if(is_processed) return true;
- // ...
- is_processed = true;
- return true;
- }
- //!@pre process has been called with status success
- //!@throw std::logic_error if preconditions not met
- std::map<std::string, std::size_t>
- result() const {
- if(!is_processed)
- throw std::runtime_error("\"process\" has not been called or was not successful");
- return histogram;
- }
- private:
- bool is_processed;
- std::ifstream fileStream_;
- std::map<std::string, std::size_t> histogram;
- };
- BOOST_AUTO_TEST_CASE( test_throw_behaviour )
- {
- // __FILE__ is accessible, no exception expected
- BOOST_REQUIRE_NO_THROW( FileWordHistogram(__FILE__) );
- // ".. __FILE__" does not exist, API says std::exception, and implementation
- // raises std::runtime_error child of std::exception
- BOOST_CHECK_THROW( FileWordHistogram(".." __FILE__), std::exception );
- {
- FileWordHistogram instance(__FILE__);
- // api says "std::logic_error", implementation is wrong.
- // std::runtime_error not a child of std::logic_error, not intercepted
- // here.
- BOOST_CHECK_THROW(instance.result(), std::logic_error);
- }
- }
- //]
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