code: def test_str():
      s = "hydrogen fluoride"
      s = hashstr(s)
      s1 = "df4e3775493a2e784618edaf9e96b7ecb6ce2b4cd022e8619588d55009872bb2"
      assert s == s1
  
imports: import pytest
label_desc: Use image node_id 4 for calling a global function with example usage: test_str() without return types