Remove too-simple test, add tests for the variants of minmax_element

Author: mclow

minmax/fuzzing/minmax.fuzz.cpp

@@ -4,8 +4,10 @@
 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include <iterator> // for std::distance
+#include <cassert>  // for assert
 
 #include <boost/algorithm/minmax_element.hpp>
+#include <boost/algorithm/cxx11/none_of.hpp>
 
 //	Fuzzing tests for:
 //
@@ -29,42 +31,50 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t sz) {
 //	Find the min and max
 	result_t result = boost::minmax_element(data, data + sz);
 
-//	The iterators have to be in the sequence
-	if (std::distance(data, result.first)  >= sz) return 1;
-	if (std::distance(data, result.second) >= sz) return 1;
+//	The iterators have to be in the sequence - and not at the end!
+	assert(std::distance(data, result.first)  < sz);
+	assert(std::distance(data, result.second) < sz);
 
 //	the minimum element can't be bigger than the max element
 	uint8_t min_value = *result.first;
 	uint8_t max_value = *result.second;
 
-	if (max_value < min_value) return 2;
+	assert(min_value <= max_value);
 
 //	None of the elements in the sequence can be less than the min, nor greater than the max
 	for (size_t i = 0; i < sz; ++i) {
-		if (data[i] < min_value) return 3;
-		if (max_value < data[i]) return 3;
+		assert(min_value <= data[i]);
+		assert(data[i] <= max_value);
 		}
+
+//	We returned the first min element, and the first max element
+	assert(boost::algorithm::none_of_equal(data, result.first,  min_value));
+	assert(boost::algorithm::none_of_equal(data, result.second, max_value));
 	}
 
 	{
 //	Find the min and max
 	result_t result = boost::minmax_element(data, data + sz, greater);
 
-//	The iterators have to be in the sequence
-	if (std::distance(data, result.first)  >= sz) return 1;
-	if (std::distance(data, result.second) >= sz) return 1;
+//	The iterators have to be in the sequence - and not at the end!
+	assert(std::distance(data, result.first)  < sz);
+	assert(std::distance(data, result.second) < sz);
 
 //	the minimum element can't be bigger than the max element
 	uint8_t min_value = *result.first;
 	uint8_t max_value = *result.second;
 
-	if (greater(max_value, min_value)) return 2;
+	assert (!greater(max_value, min_value));
 
 //	None of the elements in the sequence can be less than the min, nor greater than the max
 	for (size_t i = 0; i < sz; ++i) {
-		if (greater(data[i], min_value)) return 3;
-		if (greater(max_value, data[i])) return 3;
+		assert(!greater(data[i], min_value));
+		assert(!greater(max_value, data[i]));
 		}
+
+//	We returned the first min element, and the first max element
+	assert(boost::algorithm::none_of_equal(data, result.first,  min_value));
+	assert(boost::algorithm::none_of_equal(data, result.second, max_value));
 	}
 
   return 0;

minmax/fuzzing/minmax_element.fuzz.cpp

@@ -0,0 +1,139 @@
+//  (C) Copyright Marshall Clow 2018
+//  Use, modification and distribution are subject to 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)
+
+#include <iterator> // for std::distance
+#include <cassert>  // for assert
+
+#include <boost/algorithm/minmax_element.hpp>
+#include <boost/algorithm/cxx11/none_of.hpp>
+
+//	Fuzzing tests for:
+//
+//		template <class ForwardIterator>
+//		std::pair<ForwardIterator,ForwardIterator>
+//		first_min_first_max_element(ForwardIterator first, ForwardIterator last);
+//
+//		template <class ForwardIterator, class BinaryPredicate>
+//		std::pair<ForwardIterator,ForwardIterator>
+//		first_min_first_max_element(ForwardIterator first, ForwardIterator last,
+//	               		BinaryPredicate comp);
+//
+//	identical signatures for:
+//		first_min_last_max_element
+//		last_min_first_max_element
+//		last_min_last_max_element
+
+bool greater(uint8_t lhs, uint8_t rhs) { return lhs > rhs; }
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t sz) {
+	typedef std::pair<const uint8_t *, const uint8_t *> result_t;
+	const uint8_t * const dend = data + sz;
+	if (sz == 0) return 0; // we need at least one element
+	
+	{
+//	Find the min and max
+	result_t resultff = boost::first_min_first_max_element(data, dend);
+	result_t resultfl = boost::first_min_last_max_element (data, dend);
+	result_t resultlf = boost::last_min_first_max_element (data, dend);
+	result_t resultll = boost::last_min_last_max_element  (data, dend);
+
+//	The iterators have to be in the sequence - and not at the end!
+	assert(std::distance(data, resultff.first)  < sz);
+	assert(std::distance(data, resultff.second) < sz);
+	assert(std::distance(data, resultfl.first)  < sz);
+	assert(std::distance(data, resultfl.second) < sz);
+	assert(std::distance(data, resultlf.first)  < sz);
+	assert(std::distance(data, resultlf.second) < sz);
+	assert(std::distance(data, resultll.first)  < sz);
+	assert(std::distance(data, resultll.second) < sz);
+	
+//	the minimum element can't be bigger than the max element
+
+//	Did we find the same min value and max value?
+	uint8_t min_value = *resultff.first;
+	uint8_t max_value = *resultff.second;
+	assert(min_value <= max_value);
+
+	assert(*resultff.first  == min_value);
+	assert(*resultfl.first  == min_value);
+	assert(*resultlf.first  == min_value);
+	assert(*resultll.first  == min_value);
+
+	assert(*resultff.second == max_value);
+	assert(*resultfl.second == max_value);
+	assert(*resultlf.second == max_value);
+	assert(*resultll.second == max_value);
+
+//	None of the elements in the sequence can be less than the min, nor greater than the max
+	for (size_t i = 0; i < sz; ++i) {
+		assert(min_value <= data[i]);
+		assert(data[i] <= max_value);
+		}
+
+//	Make sure we returned the "right" first and last element
+	assert(boost::algorithm::none_of_equal(data, resultff.first,     min_value));
+	assert(boost::algorithm::none_of_equal(data, resultfl.first,     min_value));
+	assert(boost::algorithm::none_of_equal(resultlf.first + 1, dend, min_value));
+	assert(boost::algorithm::none_of_equal(resultll.first + 1, dend, min_value));
+
+	assert(boost::algorithm::none_of_equal(data, resultff.second,     max_value));
+	assert(boost::algorithm::none_of_equal(resultfl.second + 1, dend, max_value));
+	assert(boost::algorithm::none_of_equal(data, resultlf.second,     max_value));
+	assert(boost::algorithm::none_of_equal(resultll.second + 1, dend, max_value));
+	}
+	
+	{
+//	Find the min and max
+	result_t resultff = boost::first_min_first_max_element(data, dend, greater);
+	result_t resultfl = boost::first_min_last_max_element (data, dend, greater);
+	result_t resultlf = boost::last_min_first_max_element (data, dend, greater);
+	result_t resultll = boost::last_min_last_max_element  (data, dend, greater);
+
+//	The iterators have to be in the sequence - and not at the end!
+	assert(std::distance(data, resultff.first)  < sz);
+	assert(std::distance(data, resultff.second) < sz);
+	assert(std::distance(data, resultfl.first)  < sz);
+	assert(std::distance(data, resultfl.second) < sz);
+	assert(std::distance(data, resultlf.first)  < sz);
+	assert(std::distance(data, resultlf.second) < sz);
+	assert(std::distance(data, resultll.first)  < sz);
+	assert(std::distance(data, resultll.second) < sz);
+
+//	the minimum element can't be bigger than the max element
+	uint8_t min_value = *resultff.first;
+	uint8_t max_value = *resultff.second;
+	
+	assert (!greater(max_value, min_value));
+
+	assert(*resultff.first  == min_value);
+	assert(*resultfl.first  == min_value);
+	assert(*resultlf.first  == min_value);
+	assert(*resultll.first  == min_value);
+
+	assert(*resultff.second == max_value);
+	assert(*resultfl.second == max_value);
+	assert(*resultlf.second == max_value);
+	assert(*resultll.second == max_value);
+
+//	None of the elements in the sequence can be less than the min, nor greater than the max
+	for (size_t i = 0; i < sz; ++i) {
+		assert(!greater(data[i], min_value));
+		assert(!greater(max_value, data[i]));
+		}
+
+//	We returned the first min element, and the first max element
+	assert(boost::algorithm::none_of_equal(data, resultff.first,     min_value));
+	assert(boost::algorithm::none_of_equal(data, resultfl.first,     min_value));
+	assert(boost::algorithm::none_of_equal(resultlf.first + 1, dend, min_value));
+	assert(boost::algorithm::none_of_equal(resultll.first + 1, dend, min_value));
+
+	assert(boost::algorithm::none_of_equal(data, resultff.second,     max_value));
+	assert(boost::algorithm::none_of_equal(resultfl.second + 1, dend, max_value));
+	assert(boost::algorithm::none_of_equal(data, resultlf.second,     max_value));
+	assert(boost::algorithm::none_of_equal(resultll.second + 1, dend, max_value));
+	}
+
+  return 0;
+}