Your file must be named test_cases.cpp
It should start with the following code:
#include <iostream>
using namespace std;
/**
* Number Tester function
* Requires: nothing
* Modifies: nothing
* Effects: Returns the string "valid" if number is greater than 7000, even, and contains a 7
* else, returns the string "invalid"
*/
string number_tester(int input);
int main() {
// Call your testing function(s) here
return 0;
}