Add: unit test functionality using catch2

src/tests/math_func.cpp

@@ -0,0 +1,77 @@
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file math_func_test.cpp Test functionality from core/math_func. */
+
+#include "../stdafx.h"
+
+#include "../3rdparty/catch2/catch.hpp"
+
+#include "../core/math_func.hpp"
+
+TEST_CASE("LeastCommonMultipleTest - Zero")
+{
+	CHECK(0 == LeastCommonMultiple(0, 0));
+	CHECK(0 == LeastCommonMultiple(0, 600));
+	CHECK(0 == LeastCommonMultiple(600, 0));
+}
+
+TEST_CASE("LeastCommonMultipleTest - FindLCM")
+{
+	CHECK(25 == LeastCommonMultiple(5, 25));
+	CHECK(25 == LeastCommonMultiple(25, 5));
+	CHECK(130 == LeastCommonMultiple(5, 26));
+	CHECK(130 == LeastCommonMultiple(26, 5));
+}
+
+TEST_CASE("GreatestCommonDivisorTest - Negative")
+{
+	CHECK(4 == GreatestCommonDivisor(4, -52));
+	// CHECK(3 == GreatestCommonDivisor(-27, 6)); // error - returns -3
+}
+
+TEST_CASE("GreatestCommonDivisorTest - Zero")
+{
+	CHECK(27 == GreatestCommonDivisor(0, 27));
+	CHECK(27 == GreatestCommonDivisor(27, 0));
+}
+
+TEST_CASE("GreatestCommonDivisorTest - FindGCD")
+{
+	CHECK(5 == GreatestCommonDivisor(5, 25));
+	CHECK(5 == GreatestCommonDivisor(25, 5));
+	CHECK(1 == GreatestCommonDivisor(7, 27));
+	CHECK(1 == GreatestCommonDivisor(27, 7));
+}
+
+TEST_CASE("DivideApproxTest - Negative")
+{
+	CHECK(-2 == DivideApprox(-5, 2));
+	CHECK(2 == DivideApprox(-5, -2));
+	CHECK(-1 == DivideApprox(-66, 80));
+}
+
+TEST_CASE("DivideApproxTest, Divide")
+{
+	CHECK(2 == DivideApprox(5, 2));
+	CHECK(3 == DivideApprox(80, 30));
+	CHECK(3 == DivideApprox(8, 3));
+	CHECK(0 == DivideApprox(3, 8));
+}
+
+TEST_CASE("IntSqrtTest - Zero")
+{
+	CHECK(0 == IntSqrt(0));
+}
+
+TEST_CASE("IntSqrtTest - FindSqRt")
+{
+	CHECK(5 == IntSqrt(25));
+	CHECK(10 == IntSqrt(100));
+	CHECK(9 == IntSqrt(88));
+	CHECK(1696 == IntSqrt(2876278));
+}