[FEAT] Matrix add dertminant

tests/03_matrix.cpp

@@ -227,3 +227,15 @@ TEST_CASE("[Matrix] Transposing the identity matrix", "[Matrix]")
 
     REQUIRE(a == Matrix::identity());
 }
+
+/* ------------------------------------------------------------------------- */
+
+TEST_CASE("[Matrix] Calculating the determinant of a 2x2 matrix", "[Matrix]")
+{
+    Matrix a = {
+        { 1, 5},
+        {-3, 2}
+    };
+
+    REQUIRE(a.determinant() == 17);
+}