Add some unit tests for helper functions

src/unittest/test_helpers.cpp

@@ -6,7 +6,7 @@
 #include "helpers.hpp"
 #include "triangle.hpp"
 
-TEST_CASE("Test is_within_shape", "[Triangles]") {
+TEST_CASE("Test is_within_shape", "Helpers") {
     Tri::Triangle triangle({{
         {0.0f, 10.0f},
         {10.0f, 10.0f},
@@ -18,3 +18,56 @@ TEST_CASE("Test is_within_shape", "[Triangles]") {
     CHECK(Tri::is_within_shape(triangle, {15.0f, 5.0f}) == false);
     CHECK(Tri::is_within_shape(triangle, {7.0f, 7.0f}) == true);
 }
+
+TEST_CASE("Test make_counter_clockwise", "Helpers") {
+    // Note that +x is right and +y is down.
+
+    {
+        // Clockwise triangle.
+        std::array<glm::vec2, 3> tri{{
+            {0.0F, 0.0F}, {1.0F, 0.0F}, {2.0F, 2.0F}
+        }};
+
+        Tri::make_counter_clockwise(tri);
+
+        CHECK(tri.at(0).x == 2.0F);
+        CHECK(tri.at(0).y == 2.0F);
+
+        CHECK(tri.at(1).x == 1.0F);
+        CHECK(tri.at(1).y == 0.0F);
+
+        CHECK(tri.at(2).x == 0.0F);
+        CHECK(tri.at(2).y == 0.0F);
+    }
+
+    {
+        // Counter-Clockwise triangle.
+        std::array<glm::vec2, 3> tri{{
+            {2.0F, 0.0F}, {3.0F, 3.0F}, {4.0F, 1.0F}
+        }};
+
+        Tri::make_counter_clockwise(tri);
+
+        CHECK(tri.at(0).x == 2.0F);
+        CHECK(tri.at(0).y == 0.0F);
+
+        CHECK(tri.at(1).x == 3.0F);
+        CHECK(tri.at(1).y == 3.0F);
+
+        CHECK(tri.at(2).x == 4.0F);
+        CHECK(tri.at(2).y == 1.0F);
+    }
+}
+
+TEST_CASE("Test invert_color", "Helpers") {
+    Color c{
+        255, 255, 255, 255
+    };
+
+    c = Tri::invert_color(c);
+
+    CHECK(c.r == 0);
+    CHECK(c.g == 0);
+    CHECK(c.b == 0);
+    CHECK(c.a == 255);
+}