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本篇内容主要讲解“怎么用Jupyter Notebook教Python”,感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷,实用性强。下面就让小编来带大家学习“怎么用Jupyter Notebook教Python”吧!
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首先,需要一些“胶布”。通常,你会使用一些漂亮的命令行测试器来做测试,比如 pytest 或 virtue。通常,你甚至不会直接运行它。你使用像 tox 或 nox 这样的工具来运行它。然而,对于 Jupyter 来说,你需要写一小段粘合代码,可以直接在其中运行测试。
幸运的是,这个代码又短又简单:
import unittest def run_test(klass): suite = unittest.TestLoader().loadTestsFromTestCase(klass) unittest.TextTestRunner(verbosity=2).run(suite) return klass
现在,装备已经就绪,可以进行第一次练习了。
在教学中,从一个简单的练习开始,建立信心总是一个好主意。
那么,让我们来修复一个非常简单的测试:
@run_testclass TestNumbers(unittest.TestCase): def test_equality(self): expected_value = 3 # 只改这一行 self.assertEqual(1+1, expected_value)
test_equality (__main__.TestNumbers) ... FAIL ====================================================================== FAIL: test_equality (__main__.TestNumbers) ---------------------------------------------------------------------- Traceback (most recent call last): File "", line 6, in test_equality self.assertEqual(1+1, expected_value) AssertionError: 2 != 3 ---------------------------------------------------------------------- Ran 1 test in 0.002s FAILED (failures=1)
“只改这一行” 对学生来说是一个有用的标记。它准确地表明了需要修改的内容。否则,学生可以通过将第一行改为 return
来修复测试。
在这种情况下,修复很容易:
@run_testclass TestNumbers(unittest.TestCase): def test_equality(self): expected_value = 2 # 修复后的代码行 self.assertEqual(1+1, expected_value)
test_equality (__main__.TestNumbers) ... ok ---------------------------------------------------------------------- Ran 1 test in 0.002s OK
然而,很快,unittest
库的原生断言将被证明是不够的。在 pytest
中,通过重写 assert
中的字节码来解决这个问题,使其具有神奇的属性和各种启发式方法。但这在 Jupyter notebook 中就不容易实现了。是时候挖出一个好的断言库了:PyHamcrest。
from hamcrest import *@run_testclass TestList(unittest.TestCase): def test_equality(self): things = [1, 5, # 只改这一行 3] assert_that(things, has_items(1, 2, 3))
test_equality (__main__.TestList) ... FAIL ====================================================================== FAIL: test_equality (__main__.TestList) ---------------------------------------------------------------------- Traceback (most recent call last): File "", line 8, in test_equality assert_that(things, has_items(1, 2, 3)) AssertionError: Expected: (a sequence containing <1> and a sequence containing <2> and a sequence containing <3>) but: a sequence containing <2> was <[1, 5, 3]> ---------------------------------------------------------------------- Ran 1 test in 0.004s FAILED (failures=1)
PyHamcrest 不仅擅长灵活的断言,它还擅长清晰的错误信息。正因为如此,问题就显而易见了。[1, 5, 3]
不包含 2
,而且看起来很丑:
@run_testclass TestList(unittest.TestCase): def test_equality(self): things = [1, 2, # 改完的行 3] assert_that(things, has_items(1, 2, 3))
test_equality (__main__.TestList) ... ok ---------------------------------------------------------------------- Ran 1 test in 0.001s OK
使用 Jupyter、PyHamcrest 和一点测试的粘合代码,你可以教授任何适用于单元测试的 Python 主题。
例如,下面可以帮助展示 Python 从字符串中去掉空白的不同方法之间的差异。
source_string = " hello world " @run_testclass TestList(unittest.TestCase): # 这是个赠品:它可以工作! def test_complete_strip(self): result = source_string.strip() assert_that(result, all_of(starts_with("hello"), ends_with("world"))) def test_start_strip(self): result = source_string # 只改这一行 assert_that(result, all_of(starts_with("hello"), ends_with("world "))) def test_end_strip(self): result = source_string # 只改这一行 assert_that(result, all_of(starts_with(" hello"), ends_with("world")))
test_complete_strip (__main__.TestList) ... ok test_end_strip (__main__.TestList) ... FAIL test_start_strip (__main__.TestList) ... FAIL ====================================================================== FAIL: test_end_strip (__main__.TestList) ---------------------------------------------------------------------- Traceback (most recent call last): File "", line 19, in test_end_strip assert_that(result, AssertionError: Expected: (a string starting with ' hello' and a string ending with 'world') but: a string ending with 'world' was ' hello world ' ====================================================================== FAIL: test_start_strip (__main__.TestList) ---------------------------------------------------------------------- Traceback (most recent call last): File " ", line 14, in test_start_strip assert_that(result, AssertionError: Expected: (a string starting with 'hello' and a string ending with 'world ') but: a string starting with 'hello' was ' hello world ' ---------------------------------------------------------------------- Ran 3 tests in 0.006s FAILED (failures=2)
理想情况下,学生们会意识到 .lstrip()
和 .rstrip()
这两个方法可以满足他们的需要。但如果他们不这样做,而是试图到处使用 .strip()
的话:
source_string = " hello world " @run_testclass TestList(unittest.TestCase): # 这是个赠品:它可以工作! def test_complete_strip(self): result = source_string.strip() assert_that(result, all_of(starts_with("hello"), ends_with("world"))) def test_start_strip(self): result = source_string.strip() # 改完的行 assert_that(result, all_of(starts_with("hello"), ends_with("world "))) def test_end_strip(self): result = source_string.strip() # 改完的行 assert_that(result, all_of(starts_with(" hello"), ends_with("world")))
test_complete_strip (__main__.TestList) ... ok test_end_strip (__main__.TestList) ... FAIL test_start_strip (__main__.TestList) ... FAIL ====================================================================== FAIL: test_end_strip (__main__.TestList) ---------------------------------------------------------------------- Traceback (most recent call last): File "", line 19, in test_end_strip assert_that(result, AssertionError: Expected: (a string starting with ' hello' and a string ending with 'world') but: a string starting with ' hello' was 'hello world' ====================================================================== FAIL: test_start_strip (__main__.TestList) ---------------------------------------------------------------------- Traceback (most recent call last): File " ", line 14, in test_start_strip assert_that(result, AssertionError: Expected: (a string starting with 'hello' and a string ending with 'world ') but: a string ending with 'world ' was 'hello world' ---------------------------------------------------------------------- Ran 3 tests in 0.007s FAILED (failures=2)
他们会得到一个不同的错误信息,显示去除了过多的空白:
source_string = " hello world " @run_testclass TestList(unittest.TestCase): # 这是个赠品:它可以工作! def test_complete_strip(self): result = source_string.strip() assert_that(result, all_of(starts_with("hello"), ends_with("world"))) def test_start_strip(self): result = source_string.lstrip() # Fixed this line assert_that(result, all_of(starts_with("hello"), ends_with("world "))) def test_end_strip(self): result = source_string.rstrip() # Fixed this line assert_that(result, all_of(starts_with(" hello"), ends_with("world")))
test_complete_strip (__main__.TestList) ... ok test_end_strip (__main__.TestList) ... ok test_start_strip (__main__.TestList) ... ok ---------------------------------------------------------------------- Ran 3 tests in 0.005s OK
到此,相信大家对“怎么用Jupyter Notebook教Python”有了更深的了解,不妨来实际操作一番吧!这里是创新互联网站,更多相关内容可以进入相关频道进行查询,关注我们,继续学习!