assert

How can I display more info in an error message when using NUnit Assert in a loop?

由 ↘锁芯ラ 提交于 2020-01-02 01:18:07
问题 Consider the following code: [Test] public void WidgetTest() { foreach (Widget widget in widgets) { Assert.AreEqual(0, widget.SomeValue); } } If one of the asserts fails, I will get a very unhelpful error message like the one below: 1) Test Failure : WidgetTest.TestSomeValue Expected: 0 But was: 1 at WidgetTest.TestSomeValue() So, the question is, how can I get NUnit to display more useful info, such as the name of the widget, or the iteration of the loop, etc? Even a line number would be

Is assert usable in constant expressions?

由 六眼飞鱼酱① 提交于 2020-01-02 00:57:10
问题 The assert -macro from <cassert> provides a concise way of ensuring that a condition is met. If the argument evaluates to true , it shall not have any further effects. However, can its invocation also be used inside a constant expression in that case? 回答1: This was dealt with by LWG 2234, which was brought back to attention after relaxed constraints on constexpr functions had been introduced. Proposed resolution : This wording is relative to N3936. Introduce the following new definition to

Java断言assert的使用方法

由 廉价感情. 提交于 2020-01-01 20:16:16
什么时候用assert.断言是一个包含布尔表达式的语句，在执行这个语句时假定该表达式为 true.如果表达式计算为 false，那么系统会报告一个 AssertionError.它用于调试目的： assert（a > 0）； // throws an AssertionError if a <= 0断言可以有两种形式： assert Expression1 ； assert Expression1 ： Expression2 ； Expression1 应该总是产生一个布尔值。 Expression2 可以是得出一个值的任意表达式。这个值用于生成显示更多调试信息的 String 消息。 断言在默认情况下是禁用的。要在编译时启用断言，需要使用 source 1.4 标记：javac -source 1.4 Test.java要在运行时启用断言，可使用 -enableassertions 或者 -ea 标记。 要在运行时选择禁用断言，可使用 -da 或者 -disableassertions 标记。 要系统类中启用断言，可使用 -esa 或者 -dsa 标记。还可以在包的基础上启用或者禁用断言。 可以在预计正常情况下不会到达的任何位置上放置断言。断言可以用于验证传递给私有方法的参数。不过，断言不应该用于验证传递给公有方法的参数，因为不管是否启用了断言，公有方法都必须检查其参数。 不过

Python—迭代对象、迭代器、生成器

由 守給你的承諾、 提交于 2020-01-01 16:03:15
原文转载自 liuzhijun , 原文地址： https://foofish.net/iterators-vs-generators.html 本文源自 RQ 作者的一篇博文，原文是 Iterables vs. Iterators vs. Generators ，俺写的这篇文章是按照自己的理解做的参考翻译，算不上是原文的中译版本，推荐阅读原文，谢谢网友指正。 在了解Python的数据结构时，容器(container)、可迭代对象(iterable)、迭代器(iterator)、生成器(generator)、列表/集合/字典推导式(list,set,dict comprehension)众多概念参杂在一起，难免让初学者一头雾水，我将用一篇文章试图将这些概念以及它们之间的关系捋清楚。 容器(container) 容器是一种把多个元素组织在一起的数据结构，容器中的元素可以逐个地迭代获取，可以用 in , not in 关键字判断元素是否包含在容器中。通常这类数据结构把所有的元素存储在内存中（也有一些特例，并不是所有的元素都放在内存，比如迭代器和生成器对象）在Python中，常见的容器对象有： list, deque, .... set, frozensets, .... dict, defaultdict, OrderedDict, Counter, .... tuple,

python assert断言函数

由 こ雲淡風輕ζ 提交于 2020-01-01 14:34:48
本文转载自： https://www.cnblogs.com/feiyuenotes/p/7788995.html 作者：feiyueNotes 转载请注明该声明。 python assert断言是声明布尔值必须为真的判定，如果发生异常就说明表达式为假。 可以理解assert断言语句为raise-if-not，用来测试表示式，其返回值为假，就会触发异常。 self.assertEqual(a,b,msg=msg) #判断a与.b是否一致，msg类似备注，可以为空 self.assertNotEqual(a,b,msg=msg) #判断a与b是否不一致 self.assertTrue(a,msg=none) #判断a是否为True self.assertFalse(b,msg=none) #判断b是否为false self.assertAlmostEqual(a,b,places=none,msg=none,delta=none) #该判断过程有点复杂，判断过程如下 注：places与delta不能同时存在，否则出异常 #若a==b，则直接输入正确，不判断下面的过程 #若delta有数，places为空，判断a与b的差的绝对值是否<=delta，满足则正确，否则错误 #若delta为空，places有数，判断b与a的差的绝对值,取小数places位，等于0则正确，否则错误

Why is assert used in the Integer.valueOf method of the Integer class?

由 China☆狼群 提交于 2020-01-01 07:28:09
问题 I was digging into how the Integer class actually uses cached objects, and I found the below code in the Integer.valueOf method: public static Integer valueOf(int i) { assert IntegerCache.high >= 127; if (i >= IntegerCache.low && i <= IntegerCache.high) return IntegerCache.cache[i + (-IntegerCache.low)]; return new Integer(i); } My question is: what is the use of assert IntegerCache.high >= 127; I read that assert provides an effective way to detect and correct programming errors. But this is

Should one leave asserts in production iOS apps?

由 一曲冷凌霜 提交于 2020-01-01 02:41:09
问题 Common practice might be to put asserts in code to check input parameters, data integrity, and such, during app development. I test my apps, BUT, given that I'm not Knuth (and he writes $1 checks), and I can't afford to employ a large team of full-time QA people as do some medical and space systems software companies, I assume that all apps will always have plenty of bugs that have never yet been seen during testing or QA. Assuming otherwise seems quite intellectually dishonest. So after

Why are assertEquals() parameters in the order (expected, actual)?

由 社会主义新天地 提交于 2019-12-31 08:52:18
问题 Why do so many assertEquals() or similar function take the expected value as first parameter and the actual one as second ? This seems counter-intuitive to me, so is there a particular reason for this unusual order ? 回答1: Because the authors had a 50% chance of matching your intuition. Because of the other overload assertWhatever(explanation, expected, actual) And the explanation, which is part of what you know, goes with the expected, which is what you know, as opposed to the actual, which

Proper way to assert type of variable in Python

由 China☆狼群 提交于 2019-12-31 08:33:44
问题 In using a function, I wish to ensure that the type of the variables are as expected. How to do it right? Here is an example fake function trying to do just this before going on with its role: def my_print(begin, text, end): """Print 'text' in UPPER between 'begin' and 'end' in lower """ for i in (begin, text, end): assert isinstance(i, str), "Input variables should be strings" out = begin.lower() + text.upper() + end.lower() print out def test(): """Put your test cases here! """ assert my

Assert a good practice or not?

由 独自空忆成欢 提交于 2019-12-31 08:03:50
问题 Is it a good practice to use Assert for function parameters to enforce their validity. I was going through the source code of Spring Framework and I noticed that they use Assert.notNull a lot. Here's an example public static ParsedSql parseSqlStatement(String sql) { Assert.notNull(sql, "SQL must not be null");} Here's Another one: public NamedParameterJdbcTemplate(DataSource dataSource) { Assert.notNull(dataSource, "The [dataSource] argument cannot be null."); this .classicJdbcTemplate = new
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