Method IteratorGenerator

tests/catch.hpp:5772–5779

public:
	template<typename InputIterator, typename InputSentinel>
	IteratorGenerator(InputIterator first, InputSentinel last)
		: m_elems(first, last)
	{
		if (m_elems.empty()) {
			Catch::throw_exception(GeneratorException(
				"IteratorGenerator received no valid values"));
		}
	}

	T const &get() const override { return m_elems[m_current]; }