Added tests for write, and added tests/implementation of operator==. Also added implementation of FillChannel()

Test/OperatorEquals.cpp

@@ -0,0 +1,55 @@
+#include <Bmp.h>
+#include <stdexcept>
+#include "Catch2.h"
+
+using namespace Leonetienne::BmpPP;
+using namespace Eule;
+
+// Don't have to test operator not equal, because it just returns the opposite of this
+
+// Tests that two RGB images containing almost every possible color are equal, after being copied
+TEST_CASE(__FILE__"/CopiedImagesAreEqual", "[OperatorEqual]")
+{
+    // Read a gradient image
+    BMP bmp_a("base_gradient.bmp");
+
+    // Copy it
+    BMP bmp_b = bmp_a;
+
+    // Assert that they are equal
+    REQUIRE(bmp_a == bmp_b);
+    return;
+}
+
+// Tests that changing a single pixel channel results in them not being equal anymore
+TEST_CASE(__FILE__"/OneDifferingValueMakesUnequal", "[OperatorEqual]")
+{
+    // Read a gradient image
+    BMP bmp_a("base_gradient.bmp");
+
+    // Copy it
+    BMP bmp_b = bmp_a;
+
+    // Bop it
+    *(bmp_a.GetPixel(bmp_a.GetDimensions() / 2) + 1) = 69;
+
+    // Assert that they are equal
+    REQUIRE_FALSE(bmp_a == bmp_b);
+    return;
+}
+
+// Tests that two images with the exact same pixelbuffer, but differing metadata are not equal
+TEST_CASE(__FILE__"/SamePixelbufferButDifferentMetadataUnequal", "[OperatorEqual]")
+{
+    // Create image a
+    BMP bmp_a(Vector2i(800, 600), Colormode::RGB); // 1440000 values of 0
+
+    // Create image b
+    BMP bmp_b(Vector2i(600, 600), Colormode::RGBA); // Also 1440000 values of 0
+    bmp_b.FillChannel(3, 0); // Make sure the alpha channel actually is zeroed
+
+    // They only differ by their metadata. Not by pixel data. Make sure they are not euqal.
+    REQUIRE_FALSE(bmp_a == bmp_b);
+
+    return;
+}