title: How to write tests for multiple arrays of integers?
body: <p>new to Python, I would like to learn coding with Python by testing the code I write using either pytest or unittest. In that regard I'm wondering how to test assertions about multiple arrays as inputs:</p>
  
  <p>I have a function <code>extractDifferentNumber</code> which aims to return a integer doesn't belong to the rest of the sequence of integers:</p>
  
  <pre><code>def extractDifferentNumber(df):
      df_set = set(df)
      for each in df_set:
          if df.count(each) == 1:
              return each
  </code></pre>
  
  <p>which extracts that different number out of a sequence of numbers:</p>
  
  <pre><code># print(extractDifferentNumber([10,11,10,10,10,10,10])) 11
  # print(extractDifferentNumber([20,11,20,20,20]))  11
  # print(extractDifferentNumber([1,1,1,1,2])) 2
  </code></pre>
  
  <p>Now I would like to use unittest to verify that my functions returns the expected outcome:</p>
  
  <pre><code>class SingleDifferentNumberTestCase(unittest.TestCase):
      """Test for `myfunction.py`"""
  
      def setUp(self):
          self.input = [10,11,10,10,10,10,10]
          self.expected = [11]
  
      def test_is_different(self):
          """Is a number different then the others"""
          self.assertTrue(extractDifferentNumber())
  
  
  if __name__ == '__main__':
      unittest.main()
  </code></pre>
  
  <p>In that regard, I have two questions:</p>
  
  <p>How can I include multiple arrays / testcases as <code>self.input</code> and <code>self.expected</code> and how can I raise the appropriate assertion like  <code>self.assertTrue</code> for instance using unittest?</p>