import unittest
import io
import re
from unittest import mock
import math
import student_X as main #Replace student_X with your filename 
    
    
    
 

class EarlierStringTests(unittest.TestCase):

    def test_default_case(self):
        function = main.earlier_string
        
        test = False
        try:
            incorrect = ""
            result = function.__doc__
            result = result.strip()
            test = incorrect != result
        except:
            pass
        message = "No docstring."
        self.assertTrue(test, message)

        
        inputs = ("", "cheese")
        correct = ""
        if isinstance(inputs, tuple):
            result = function(*inputs)
        else:
            result = function(inputs)
        test = result == correct
        message = "Doesn't work when one of the parameters is the empty string."
        self.assertTrue(test, message)

        
        inputs = ("x", "")
        correct = ""
        if isinstance(inputs, tuple):
            result = function(*inputs)
        else:
            result = function(inputs)
        test = result == correct
        message = "Doesn't work when one of the parameters is the empty string."
        self.assertTrue(test, message)

        
        inputs = ("a", "b")
        correct = "a"
        if isinstance(inputs, tuple):
            result = function(*inputs)
        else:
            result = function(inputs)
        test = result == correct
        message = "Doesn't work on a single-character strings."
        self.assertTrue(test, message)

        
        inputs = ("b", "aa")
        correct = "aa"
        if isinstance(inputs, tuple):
            result = function(*inputs)
        else:
            result = function(inputs)
        test = result == correct
        message = "Doesn't work on some short strings."
        self.assertTrue(test, message)

        
        inputs = ("cheese", "cheese")
        correct = "cheese"
        if isinstance(inputs, tuple):
            result = function(*inputs)
        else:
            result = function(inputs)
        test = result == correct
        message = "Doesn't work when both strings are the same."
        self.assertTrue(test, message)

        
        inputs = ("cinnaman", "apple")
        correct = "apple"
        if isinstance(inputs, tuple):
            result = function(*inputs)
        else:
            result = function(inputs)
        test = result == correct
        message = "Doesn't work on longer strings."
        self.assertTrue(test, message)
        
        
if __name__ == "__main__":
    tests = EarlierStringTests()
    tests.test_default_case()