单元测试设计

Question

几天前，我写了一段代码作为面试的一部分。题目是给定一段文本，找出查询的文本是否存在于这段文本中。我使用了哈希表来保存这段文本（键是文本中的单词，值是这些单词在文本中的位置）。所以现在给定查询字符串，我可以找到文本中存在的单词的位置，并显示包含最多查询单词的文本片段。我觉得一切都很好。

但是我还被要求为这段代码写单元测试。虽然我之前从未写过单元测试，但我知道它们在开发过程中是多么重要。因此，我创建了一些测试用例，考虑了平均情况和边界情况。但我不太清楚的是，写测试用例时是否需要提前知道正确的输出。

我开始获取一些文本作为程序的输入，以及相应的输出，把它们放在一个类里，之后作为输入读取到我的程序中。

下面是单元测试的代码：

import unittest
import random
import generate_random_test
class c_Known_Output():
Input_Text1 = '''We ordered the traditional deep dish pizza and a Manchego salad. Were started off with a complimentary bread, that looks like a really big hamburger bun top at first glance. Even though it was free bread, it was soft and slightly sweet and delicious. I liked dipping it in the balsamic reduction and olive oil from the salad plate. The salad dish was perfectly fine, but I wish the Manchego slices on top were somehow sliced a bit thinner. The deep dish traditional pizza came out a bit later (remember the 40 min. cooking time, folks!), piping hot and smelling delicious. At first bite, I wasnt sure how much I liked it.'''

Output_Text1 = '''I liked dipping it in the balsamic reduction and olive oil from the salad plate. The salad [[HIGHLIGHT]]dish[[ENDHIGHLIGHT]] was perfectly fine, but I wish the Manchego slices on top were somehow sliced a bit thinner. The [[HIGHLIGHT]]deep dish[[ENDHIGHLIGHT]] traditional pizza came out a bit later (remember the 40 min. cooking time, folks!), piping hot and smelling delicious.'''

Input_Text2 = '''Best tacos I have ever had Lived down the road from this truck for years. Watched almost every episode of BSG eating these tacos with beer. Moved to Az and El Chato is one of the things I miss the most! ANYONE that is around them, you have to go here.'''

Output_Text2 = '''Best [[HIGHLIGHT]]tacos[[ENDHIGHLIGHT]] I have ever had Lived down the road from this truck for years. Watched almost every episode of BSG eating these [[HIGHLIGHT]]tacos[[ENDHIGHLIGHT]] with beer. Moved to Az and El Chato is one of the things I miss the most!'''

Query_Not_found = '''Query Not Found'''


class c_myTest( unittest.TestCase ):
Generator = generate_random_test.TestCaseGenerator()
KnowOutput = c_Known_Output()

def testAverageCase1(self):
    """no keywords present...no highlight"""
    output = highlight.m_Highlight_doc( self.KnowOutput.Input_Text1, 'deep dish')
    print "\nTest Case 1"
    print output
    self.assertEqual(output, self.KnowOutput.Output_Text1)

def testAverageCase2(self):
    output = highlight.m_Highlight_doc( self.KnowOutput.Input_Text2, 'burrito taco take out')
    print "\nTest Case 2"
    print output
    self.assertEqual(output, self.KnowOutput.Output_Text2)

def testSnippetLength(self):
    """ if the search word is present only once in the text...check if the snippet is of optimum length...optimum length is defined as one sentence before
    and after the sentence in which the query word is present"""
    output = highlight.m_Highlight_doc( self.KnowOutput.Input_Text3, 'tacos')
    print "\nTest Case 3"
    print output
    self.assertEqual(output, self.KnowOutput.Output_Text3)

def testSmallText(self):
    """The text is just one sentence, with the query present in it. The same sentence should be the output"""
    output = highlight.m_Highlight_doc( self.KnowOutput.Input_Text4, 'deep dish pizzas')
    print "\nTest Case 4"
    print output
    self.assertEqual(output, self.KnowOutput.Output_Text4)

def testBadInput(self):
    """no keywords present...no highlight"""
    output = highlight.m_Highlight_doc( self.KnowOutput.Input_Text4, 'tacos')
    print "\nTest Case 5"
    print output
    self.assertEqual(output, self.KnowOutput.Query_Not_found)

#Now test with randomly generated text
def testDistantKeywords(self):
    """the search queries are very distant in the text. 6 query words are generated. First 4 of these queries are inserted in one paragraph and the last two
    queries are inserted in another. The snippet should be of the first paragraph which has the maximum number of query words present in it."""
    query = self.Generator.generateSentence(6, 5)
    text1 = self.Generator.generateTextwithQuery( query[0:4], 10, 10, 5, 3 )
    text2 = self.Generator.generateTextwithQuery( query[5:], 10, 10, 5, 3 )
    text1.append('\n')
    text1.extend(text2)
    print "\nTest Case 6"
    print "=========================TEXT=================="
    print ' '.join(text1)
    print "========================QUERY=================="
    print ' '.join(query)
    print " "
    output_text = highlight.m_Highlight_doc( ' '.join(text1), ' '.join(query))
    print "=======================SNIPPET================="
    print output_text
    print " "


if __name__=='__main__':
    unittest.main()

显然我失败了，但没有人告诉我原因，现在我正在努力弄清楚这段代码是否有问题。有人能帮我找出单元测试中的问题吗？如果你提前知道代码的输出，该怎么写单元测试呢？比如，我们能为随机数生成器写单元测试吗？

提前谢谢大家！！！

文本处理单元测试测试用例代码质量哈希表软件开发随机数生成器边界情况

单元测试设计

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