text: import pytest
  from hash_tables.hashtable import HashTable
  from hash_tables.hashmap_left_join import left_join
  
  
  def test_left_join_empty_hashmap():
      ht1 =HashTable ()
      ht2 =HashTable ()
      assert left_join(ht1 , ht2) == []
  
  def test_left_join_hashmap():
      ht1 = HashTable()
      ht1.addItem("fond", "enamored")
      ht1.addItem("wrath", "anger")
      ht1.addItem("diligent", "employed")
      ht1.addItem("outfit", "garb")
      ht1.addItem("guide", "usher")
  
      ht2 = HashTable()
      ht2.addItem("fond", "averse")
      ht2.addItem("wrath", "delight")
      ht2.addItem("diligent", "idle")
      ht2.addItem("guide", "follow")
      ht2.addItem("flow", "jam")
  
      assert left_join(ht1, ht2) == [['fond', 'enamored', 'averse'], ['guide', 'usher', 'follow'], ['wrath', 'anger', 'delight'], ['outfit', 'garb', None], ['diligent', 'employed', 'idle'], ['flow', None, 'jam']]