Add preliminary working principle of unit tests

test/geometric/vector-operations.cpp

@@ -0,0 +1,43 @@
+#include <catch.hpp>
+#include <limits>
+
+extern "C" {
+#include <gds-render/geometric/vector-operations.h>
+}
+
+TEST_CASE("geometric/vector-operations/vector_2d_add", "[GEOMETRIC]")
+{
+	struct vector_2d res;
+	struct vector_2d a;
+	struct vector_2d b;
+
+	a.x = 1;
+	a.y = 2;
+
+	b.x = 2;
+	b.y = 6;
+
+	vector_2d_add(&res, &a, &b);
+
+	REQUIRE(res.x == Approx(a.x + b.x));
+	REQUIRE(res.y == Approx(a.y + b.y));
+}
+
+TEST_CASE("geometric/vector-operations/vector_2d_calculate_angle_between", "[GEOMETRIC]")
+{
+	double angle;
+	struct vector_2d a;
+	struct vector_2d b;
+
+	a.x = 1;
+	a.y = 0;
+
+	b.x = 0;
+	b.y = 1;
+
+	angle = vector_2d_calculate_angle_between(&a, &a);
+	REQUIRE(angle == Approx(0.0));
+
+	angle = vector_2d_calculate_angle_between(&a, &b);
+	REQUIRE(angle == Approx(90.0 / 180.0 * M_PI));
+}