How to initialize class object with array reference passed as a template argument to constructor in C++ 17 using braced initializator?

I have a template class and want to pass a reference to an array in its constructor, using braced initializator.

template<typename T, size_t ar_sz> class Test_class {
    // Thats incorrect
    /*
    T t;
    size_t size;
    */
    
    // Thats correct?
    T array[ar_sz];
public:

    Test_class(const T (&array)[ar_sz]) {
    }

};

int main() {
  
    constexpr size_t array_sz = 1;
    int ar_i[array_sz]{ 1 };

    Test_class test_ar{ ar_i };

}

So how to properly do that?

EDIT:

I want to add that i need to pass L"test" to a constructor, which is a const wchar_t[5], so this task cant be resolved using std::array<>

The compiler deduces T = int and ar_sz = 1. In your template, declaration T t; means the same as int t;. You don't want this! You want T t[ar_sz];. BTW to reduce confusion, use array size greater than 1.

Another problem is (as other people noted): you can't initialize an array using another array. You need explicit copying.

#include <iostream>
#include <algorithm>

template<typename T, size_t size> 
struct Test
{
public:
    T m_values[size]; // array, not element (you could also use std::array)

    Test(const T (&values)[size])
    {
    	std::copy(values, values + size, m_values); // explicit copying (you could also use memcpy)
    }

    const auto& values() const noexcept
    {
        return m_values;
    }
};

int main() 
{
    Test test("meh");

    std::cout << test.values()[1] << '\n';
    std::cout << test.values()[2] << '\n';
    return 0;
}

Use std::array as already suggested, also when initializing you need an extra pair of {} to pass the values.

#include <array>
#include <iostream>

template<typename T, size_t ar_sz> 
class Test_class 
{
public:
    Test_class(const std::array<T,ar_sz>& values) : 
        m_values{ values } 
    {
    }

    const auto& values() const noexcept
    {
        return m_values;
    }

private:
    std::array<T, ar_sz> m_values;

};

int main() 
{
    std::array values{ 1,2,3 };
    Test_class test_ar{ values };     

    std::cout << test_ar.values()[2];
    return 0;
}