Unit tests for Vector2 extensions

Also adds ApproxVec and ApproxDeg types for more readable comparison of approximate vectors/angles.

test/System/Vector2.cpp

@@ -4,7 +4,12 @@
 
 #include <doctest.h>
 
-// Use sf::Vector2i for tests. Test coverage is given, as there are no template specializations.
+using namespace sf::Literals;
+using doctest::Approx;
+
+// Use sf::Vector2i for tests (except for float vector algebra).
+// Test coverage is given, as there are no template specializations.
+
 
 TEST_CASE("sf::Vector2 class template - [system]")
 {
@@ -184,11 +189,97 @@ TEST_CASE("sf::Vector2 class template - [system]")
         }
     }
 
+    SUBCASE("Length and normalization")
+    {
+        sf::Vector2f v(2.4f, 3.0f);
+
+        CHECK(v.length() == Approx(3.84187));
+        CHECK(v.lengthSq() == Approx(14.7599650969));
+        CHECK(v.normalized() == ApproxVec(0.624695, 0.780869));
+
+        sf::Vector2f w(-0.7f, -2.2f);
+        
+        CHECK(w.length() == Approx(2.30868));
+        CHECK(w.lengthSq() == Approx(5.3300033));
+        CHECK(w.normalized() == ApproxVec(-0.303204, -0.952926));
+    }
+
+    SUBCASE("Rotations and angles")
+    {
+        sf::Vector2f v(2.4f, 3.0f);
+        
+        CHECK(v.angle() == ApproxDeg(51.3402));
+        CHECK(sf::Vector2f::UnitX.angleTo(v) == ApproxDeg(51.3402));
+        CHECK(sf::Vector2f::UnitY.angleTo(v) == ApproxDeg(-38.6598));
+
+        sf::Vector2f w(-0.7f, -2.2f);
+
+        CHECK(w.angle() == ApproxDeg(-107.65));
+        CHECK(sf::Vector2f::UnitX.angleTo(w) == ApproxDeg(-107.65));
+        CHECK(sf::Vector2f::UnitY.angleTo(w) == ApproxDeg(162.35));
+
+        CHECK(v.angleTo(w) == ApproxDeg(-158.9902));
+        CHECK(w.angleTo(v) == ApproxDeg(158.9902));
+
+        float ratio = w.length() / v.length();
+        CHECK(v.rotatedBy(-158.9902_deg) * ratio  == ApproxVec(w));
+        CHECK(w.rotatedBy(158.9902_deg) / ratio == ApproxVec(v));
+
+        CHECK(v.perpendicular() == sf::Vector2f(-3.0f, 2.4f));
+        CHECK(v.perpendicular().perpendicular().perpendicular().perpendicular() == v);
+
+        CHECK(v.rotatedBy(90_deg) == ApproxVec(-3.0, 2.4));
+        CHECK(v.rotatedBy(27.14_deg) == ApproxVec(0.767248, 3.76448));
+        CHECK(v.rotatedBy(-36.11_deg) == ApproxVec(3.70694, 1.00925));
+    }
+    
+    SUBCASE("Products and quotients")
+    {
+        sf::Vector2f v(2.4f, 3.0f);
+        sf::Vector2f w(-0.7f, -2.2f);
+
+        CHECK(v.dot(w) == Approx(-8.28));
+        CHECK(w.dot(v) == Approx(-8.28));
+
+        CHECK(v.cross(w) == Approx(-3.18));
+        CHECK(w.cross(v) == Approx(+3.18));
+        
+        CHECK(v.cwiseMul(w) == ApproxVec(-1.68, -6.6));
+        CHECK(w.cwiseMul(v) == ApproxVec(-1.68, -6.6));
+        CHECK(v.cwiseDiv(w) == ApproxVec(-3.428571, -1.363636));
+        CHECK(w.cwiseDiv(v) == ApproxVec(-0.291666, -0.733333));
+    }
+    
+    SUBCASE("Projection")
+    {
+        sf::Vector2f v(2.4f, 3.0f);
+        sf::Vector2f w(-0.7f, -2.2f);
+        
+        CHECK(v.projectedOnto(w) == ApproxVec(1.087430, 3.417636));
+        CHECK(v.projectedOnto(w) == ApproxVec(-1.55347f * w));
+
+        CHECK(w.projectedOnto(v) == ApproxVec(-1.346342, -1.682927));
+        CHECK(w.projectedOnto(v) == ApproxVec(-0.560976f * v));
+
+        CHECK(v.projectedOnto(sf::Vector2f::UnitX) == ApproxVec(2.4, 0.0));
+        CHECK(v.projectedOnto(sf::Vector2f::UnitY) == ApproxVec(0.0, 3.0));
+    }
+
     SUBCASE("Constexpr support")
     {
-        constexpr sf::Vector2i vector(1, 2);
-        static_assert(vector.x == 1);
-        static_assert(vector.y == 2);
-        static_assert(vector + sf::Vector2i(2, 1) == sf::Vector2i(3, 3));
+        constexpr sf::Vector2i v(1, 2);
+        constexpr sf::Vector2i w(2, -3);
+
+        static_assert(v.x == 1);
+        static_assert(v.y == 2);
+        static_assert(v + w == sf::Vector2i(3, -1));
+
+        static_assert(v.lengthSq() == 5);
+        static_assert(v.perpendicular() == sf::Vector2i(-2, 1));
+
+        static_assert(v.dot(w) == -4);
+        static_assert(v.cross(w) == -7);
+        static_assert(v.cwiseMul(w) == sf::Vector2i(2, -6));
+        static_assert(w.cwiseDiv(v) == sf::Vector2i(2, -1));
     }
 }

test/TestUtilities/SystemUtil.cpp

@@ -4,6 +4,7 @@
 #include <SFML/System/String.hpp>
 #include <SFML/System/Time.hpp>
 
+#include <doctest.h> // for Approx
 #include <cassert>
 #include <filesystem>
 #include <fstream>
@@ -34,6 +35,28 @@ namespace sf
     }
 }
 
+bool operator==(const sf::Vector2f& lhs, const ApproxVec& rhs)
+{
+    return (lhs - rhs.vector).length() == doctest::Approx(0.0);
+}
+
+bool operator==(const sf::Angle& lhs, const ApproxDeg& rhs)
+{
+    return lhs.asDegrees() == doctest::Approx(rhs.degrees);
+}
+
+std::ostream& operator <<(std::ostream& os, const ApproxVec& approx)
+{
+    os << approx.vector;
+    return os;
+}
+
+std::ostream& operator <<(std::ostream& os, const ApproxDeg& approx)
+{
+    os << sf::degrees(approx.degrees);
+    return os;
+}
+
 namespace sf::Testing
 {
     static std::string getTemporaryFilePath()

test/TestUtilities/SystemUtil.hpp

@@ -39,6 +39,33 @@ namespace sf
     }
 }
 
+// Utilities for approximate equality
+struct ApproxVec
+{
+    ApproxVec(double x, double y)
+        : vector(static_cast<float>(x), static_cast<float>(y)) {}
+
+    explicit ApproxVec(const sf::Vector2f& v)
+        : vector(v) {}
+
+    sf::Vector2f vector;
+};
+
+// Utilities for approximate equality
+struct ApproxDeg
+{
+    ApproxDeg(double degrees)
+        : degrees(static_cast<float>(degrees)) {}
+
+    float degrees;
+};
+
+bool operator==(const sf::Vector2f& lhs, const ApproxVec& rhs);
+bool operator==(const sf::Angle& lhs, const ApproxDeg& rhs);
+
+std::ostream& operator <<(std::ostream& os, const ApproxVec& approx);
+std::ostream& operator <<(std::ostream& os, const ApproxDeg& approx);
+
 namespace sf::Testing
 {
     class TemporaryFile