diff --git a/tests/test.cpp b/tests/test.cpp
index cd0874c..8810825 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -1,10 +1,198 @@
 #include "../s2ga.hpp"
 #include <catch2/catch_all.hpp>
+#include <catch2/catch_approx.hpp>
 #include <catch2/catch_test_macros.hpp>
-#include <iostream>
+#include <catch2/matchers/catch_matchers_range_equals.hpp>
+#include <cmath>
+#include <numbers>
+
+using namespace Catch;
+
+constexpr double TOLERANCE = 1e-4;
+
+inline double sphere(double x, double y)
+{
+    return std::pow(x, 2.0) + std::pow(y, 2.0);
+}
+
+TEST_CASE("sphere(0, 0) = 0")
+{
+    REQUIRE(sphere(0.0, 0.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double ackley(double x, double y)
+{
+    return -20.0 * std::exp(-0.2 * std::sqrt(0.5 * sphere(x, y))) -
+           std::exp(0.5 * (std::cos(2.0 * std::numbers::pi * x) +
+                           std::cos(2.0 * std::numbers::pi * y))) +
+           std::numbers::e + 20.0;
+}
+
+TEST_CASE("ackley(0, 0) = 0")
+{
+    REQUIRE(ackley(0.0, 0.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double rastrigin(double x, double y)
+{
+    const double A = 10.0;
+    return 2.0 * A +
+           (std::pow(x, 2.0) - A * std::cos(2.0 * std::numbers::pi * x)) +
+           (std::pow(y, 2.0) - A * std::cos(2.0 * std::numbers::pi * y));
+}
+
+TEST_CASE("rastrigin(0, 0) = 0")
+{
+    REQUIRE(rastrigin(0.0, 0.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double rosenbrock(double x, double y)
+{
+    return 100.0 * std::pow(y - std::pow(x, 2.0), 2.0) + std::pow(1.0 - x, 2.0);
+}
+
+TEST_CASE("rosenbrock(1, 1) = 0")
+{
+    REQUIRE(rosenbrock(1.0, 1.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double bill(double x, double y)
+{
+    return std::pow(1.5 - x + x * y, 2.0) +
+           std::pow(2.25 - x + x * std::pow(y, 2.0), 2.0) +
+           std::pow(2.625 - x + x * std::pow(y, 3.0), 2.0);
+}
+
+TEST_CASE("bill(3, 0.5) = 0")
+{
+    REQUIRE(bill(3.0, 0.5) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double goldstein_price(double x, double y)
+{
+    return (1.0 + std::pow(x + y + 1.0, 2.0) *
+                      (19.0 - 14.0 * x + 3.0 * std::pow(x, 2.0) - 14.0 * y +
+                       6.0 * x * y + 3.0 * std::pow(y, 2.0))) *
+           (30.0 + std::pow(2.0 * x - 3.0 * y, 2.0) *
+                       (18.0 - 32.0 * x + 12.0 * std::pow(x, 2.0) + 48.0 * y -
+                        36.0 * x * y + 27.0 * std::pow(y, 2.0)));
+}
+
+TEST_CASE("goldstein_price(0, -1) = 3")
+{
+    REQUIRE(goldstein_price(0.0, -1.0) == Approx(3.0).margin(TOLERANCE));
+}
+
+inline double booth(double x, double y)
+{
+    return std::pow(x + 2.0 * y - 7.0, 2.0) + std::pow(2.0 * x + y - 5.0, 2.0);
+}
+
+TEST_CASE("booth(1, 3) = 0")
+{
+    REQUIRE(booth(1.0, 3.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double bukin_n6(double x, double y)
+{
+    return 100.0 * std::sqrt(std::abs(y - 0.01 * std::pow(x, 2.0))) +
+           0.01 * std::abs(x + 10.0);
+}
+
+TEST_CASE("bukin_n6(-10, 1) = 0")
+{
+    REQUIRE(bukin_n6(-10.0, 1.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double matyas(double x, double y)
+{
+    return 0.26 * sphere(x, y) - 0.48 * x * y;
+}
+
+TEST_CASE("matyas(0, 0) = 0")
+{
+    REQUIRE(matyas(0.0, 0.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double sin2(double x)
+{
+    return std::pow(std::sin(x), 2.0);
+}
+
+inline double levi_n13(double x, double y)
+{
+    return sin2(3.0 * std::numbers::pi * x) +
+           std::pow(x - 1.0, 2.0) * (1.0 + sin2(3.0 * std::numbers::pi * y)) +
+           std::pow(y - 1.0, 2.0) * (1.0 + sin2(2.0 * std::numbers::pi * y));
+}
+
+TEST_CASE("levi_n13(1, 1) = 0")
+{
+    REQUIRE(levi_n13(1.0, 1.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double three_hump_camel(double x, double y)
+{
+    return 2.0 * std::pow(x, 2.0) - 1.05 * std::pow(x, 4.0) +
+           std::pow(x, 6.0) / 6.0 + x * y + std::pow(y, 2.0);
+}
+
+TEST_CASE("three_hump_camel(0, 0) = 0")
+{
+    REQUIRE(three_hump_camel(0.0, 0.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double eggholder(double x, double y)
+{
+    return -(y + 47.0) * std::sin(std::sqrt(std::abs(x / 2.0 + (y + 47.0)))) -
+           x * std::sin(std::sqrt(std::abs(x - (y + 47.0))));
+}
+
+TEST_CASE("eggholder(512, 404.2319) = -959.6407")
+{
+    REQUIRE(eggholder(512.0, 404.2319) == Approx(-959.6407).margin(TOLERANCE));
+}
+
+inline double mccormick(double x, double y)
+{
+    return std::sin(x + y) + std::pow(x - y, 2.0) - 1.5 * x + 2.5 * y + 1.0;
+}
+
+TEST_CASE("mccormick(-0.54719, -1.54719) = -1.9133")
+{
+    REQUIRE(mccormick(-0.54719, -1.54719) == Approx(-1.9133).margin(TOLERANCE));
+}
+
+inline double schaffer_n2(double x, double y)
+{
+    return 0.5 + (sin2(std::pow(x, 2.0) - std::pow(y, 2.0)) - 0.5) /
+                     std::pow(1.0 + 0.001 * sphere(x, y), 2.0);
+}
+
+TEST_CASE("schaffer_n2(0, 0) = 0")
+{
+    REQUIRE(schaffer_n2(0.0, 0.0) == Approx(0.0).margin(TOLERANCE));
+}
+
+inline double cos2(double x)
+{
+    return std::pow(std::cos(x), 2.0);
+}
+
+inline double schaffer_n4(double x, double y)
+{
+    return 0.5 +
+           (cos2(std::sin(std::abs(std::pow(x, 2.0) - std::pow(y, 2.0)))) -
+            0.5) /
+               std::pow(1.0 + 0.001 * sphere(x, y), 2.0);
+}
+
+TEST_CASE("schaffer_n4(0, 1.25313) = 0.292579")
+{
+    REQUIRE(schaffer_n4(0.0, 1.25313) == Approx(0.292579).margin(TOLERANCE));
+}
 
 TEST_CASE("Should pass")
 {
-    std::cout << "HI" << std::endl;
     REQUIRE_NOTHROW(foo());
 }