Add Colour implementation

tests/colour_test.cpp

@@ -0,0 +1,51 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Colour unit tests
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#include <colour.h>
+#include <math.h>
+#include <gtest/gtest.h>
+
+TEST(ColourTest, Color_is_tuple)
+{
+    Colour c = Colour(-0.5, 0.4, 1.7);
+
+    ASSERT_EQ(c.red(), -0.5);
+    ASSERT_EQ(c.green(), 0.4);
+    ASSERT_EQ(c.blue(), 1.7);
+}
+
+TEST(ColourTest, Adding_colours)
+{
+    Colour c1 = Colour(0.9, 0.6, 0.75);
+    Colour c2 = Colour(0.7, 0.1, 0.25);
+
+    ASSERT_EQ(c1 + c2, Colour(1.6, 0.7, 1.0));
+}
+
+TEST(ColourTest, Substracting_colours)
+{
+    Colour c1 = Colour(0.9, 0.6, 0.75);
+    Colour c2 = Colour(0.7, 0.1, 0.25);
+
+    ASSERT_EQ(c1 - c2, Colour(0.2, 0.5, 0.5));
+}
+
+TEST(ColourTest, Multiplying_colour_by_a_scalar)
+{
+    Colour c = Colour(0.2, 0.3, 0.4);
+
+    ASSERT_EQ(c * 2, Colour(0.4, 0.6, 0.8));
+}
+
+TEST(ColourTest, Multiplying_colours)
+{
+    Colour c1 = Colour(1, 0.2, 0.4);
+    Colour c2 = Colour(0.9, 1, 0.1);
+
+    ASSERT_EQ(c1 * c2, Colour(0.9, 0.2, 0.04));
+}