Added implementation of Rotation methods, and tests

Test/CMakeLists.txt

@@ -28,6 +28,7 @@ add_executable(Test
         MirrorHorizontally.cpp
         MirrorVertically.cpp
         SwapChannels.cpp
+        Rotate.cpp
 )
 
 # Move test images to build dir

Test/Rotate.cpp

@@ -0,0 +1,54 @@
+#include <Bmp.h>
+#include <stdexcept>
+#include "Catch2.h"
+
+using namespace Leonetienne::BmpPP;
+using namespace Eule;
+
+// Tests that rotating works
+TEST_CASE(__FILE__"/Mirroring produces the correct results", "[Rotate]")
+{
+    SECTION("90deg clockwise") {
+        // Read an image
+        BMP bmp("base_mateya.bmp");
+
+        // Rotate it
+        bmp = bmp.Rotate90degClockwise();
+
+        // Read reference image
+        const BMP reference("base_mateya_rot_90deg.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    SECTION("90deg counterclockwise") {
+        // Read an image
+        BMP bmp("base_mateya.bmp");
+
+        // Rotate it
+        bmp = bmp.Rotate90degCounterclockwise();
+
+        // Read reference image
+        const BMP reference("base_mateya_rot_270deg.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    SECTION("180deg") {
+        // Read an image
+        BMP bmp("base_mateya.bmp");
+
+        // Rotate it
+        bmp = bmp.Rotate180deg();
+
+        // Read reference image
+        const BMP reference("base_mateya_rot_180deg.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    return;
+}