Moved rng-methods to their own class/header

Test/Random_RandomIntRange.cpp

@@ -0,0 +1,100 @@
+#include "CppUnitTest.h"
+#include "../_TestingUtilities/Testutil.h"
+#include "../Eule/Random.h"
+#include <array>
+#include <sstream>
+
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+using namespace Eule;
+
+namespace _Random
+{
+	TEST_CLASS(_RandomIntRange)
+	{
+	public:
+		// Checks that a random integer is never outside the specification, two positive values
+		TEST_METHOD(Never_Outside_Specification__pos__pos)
+		{
+			// Test 1000 random integers
+			for (std::size_t i = 0; i < 1000; i++)
+			{
+				int rnd = Random::RandomIntRange(49, 99);
+
+				Assert::IsTrue(rnd >= 49, L"rnd too small");
+				Assert::IsTrue(rnd <= 99, L"rnd too big");
+			}
+
+			return;
+		}
+
+		// Checks that a random integer is never outside the specification, negative minimum
+		TEST_METHOD(Never_Outside_Specification__neg__pos)
+		{
+			// Test 1000 random integers
+			for (std::size_t i = 0; i < 1000; i++)
+			{
+				int rnd = Random::RandomIntRange(-39, 99);
+
+				Assert::IsTrue(rnd >= -39, L"rnd too small");
+				Assert::IsTrue(rnd <= 99, L"rnd too big");
+			}
+
+			return;
+		}
+
+		// Checks that a random integer is never outside the specification, two negative values
+		TEST_METHOD(Never_Outside_Specification__neg__neg)
+		{
+			// Test 1000 random integers
+			for (std::size_t i = 0; i < 1000; i++)
+			{
+				int rnd = Random::RandomIntRange(-39, -10);
+
+				Assert::IsTrue(rnd >= -39, L"rnd too small");
+				Assert::IsTrue(rnd <= -10, L"rnd too big");
+			}
+
+			return;
+		}
+
+		// Checks that the random intrange method also returns the supplied limits
+		TEST_METHOD(Inclusivity)
+		{
+			// Test 1000 random integers
+			// The chance that any number [0,9] will not drop at least once is basically 0
+
+			std::array<bool, 10> foundDigits;
+			foundDigits.fill(false);
+
+			for (std::size_t i = 0; i < 1000; i++)
+			{
+				int randomVal = Random::RandomIntRange(0, 9);
+				foundDigits[randomVal] = true;
+			}
+
+			// Check that each value has been rolled at least once
+			for (const bool& b : foundDigits)
+				Assert::IsTrue(b);
+
+			return;
+		}
+
+		// Checks that the produced integer distribution shows a big standard deviation
+		TEST_METHOD(Big_Standard_Deviation)
+		{
+			// Setup
+			std::vector<int> rands;
+			rands.resize(1000);
+
+			// Exercise
+			// Create 1000 random values
+			std::generate_n(rands.data(), rands.size(), []()->int { return Random::RandomIntRange(100, (int)4e9); });
+			
+			// Verify
+			const double stddev = Testutil::Stddev(rands);
+			Assert::IsTrue(stddev >= 1000000, (std::wstringstream() << stddev).str().c_str());
+
+			return;
+		}
+	};
+}