Adjust function to add wiggle room to tolerance

Author: steppi

tests/testing_utils.h

@@ -1,3 +1,4 @@
+#include <algorithm>
 #include <complex>
 #include <filesystem>
 #include <iostream>
@@ -119,4 +120,11 @@ Catch::Generators::GeneratorWrapper<std::tuple<T1, T2, T3>> xsf_test_cases(
     );
 }
 
+
+template <typename T>
+T adjust_tolerance(T tol) {
+    // Add some wiggle room to tolerance from table.
+    return 2 * std::max(std::numeric_limits<T>::epsilon(), tol);
+}
+
 } // namespace