Tutorial by Examples: assertion

An assertion is a statement used to assert that a fact must be true when that line of code is reached. Assertions are useful for ensuring that expected conditions are met. When the condition passed to an assertion is true, there is no action. The behavior on false conditions depends on compiler fl...

C11 Static assertions are used to check if a condition is true when the code is compiled. If it isn't, the compiler is required to issue an error message and stop the compiling process. A static assertion is one that is checked at compile time, not run time. The condition must be a constant expres...

During development, when certain code paths must be prevented from the reach of control flow, you may use assert(0) to indicate that such a condition is erroneous: switch (color) { case COLOR_RED: case COLOR_GREEN: case COLOR_BLUE: break; default: assert(0); ...

Assert.That(actual, Is.EqualTo(expected));

Writes an error message to the console if the assertion is false. Otherwise, if the assertion is true, this does nothing. console.assert('one' === 1); Multiple arguments can be provided after the assertion–these can be strings or other objects–that will only be printed if the assertion is fals...

!! suffixes ignore nullability and returns a non-null version of that type. KotlinNullPointerException will be thrown if the object is a null. val message: String? = null println(message!!) //KotlinNullPointerException thrown, app crashes

At its most basic level, Unit Testing in any language provides assertions against some known or expected output. function assert( outcome, description ) { var passFail = outcome ? 'pass' : 'fail'; console.log(passFail, ': ', description); return outcome; }; The popular assertio...

Assertions are used not to perform testing of input parameters, but to verify that program flow is corect -- i.e., that you can make certain assumptions about your code at a certain point in time. In other words: a test done with Debug.Assert should always assume that the value tested is true. Debu...

While Python has an assert statement, the Python unit testing framework has better assertions specialized for tests: they are more informative on failures, and do not depend on the execution's debug mode. Perhaps the simplest assertion is assertTrue, which can be used like this: import unittest ...

System.assert can be used to check that a boolean expression evaluates to true: System.assert(Service.isActive()); System.assert(!Service.getItems().isEmpty(), 'items should not be empty'); System.assertEquals and System.assertNotEquals can be used to check equality of two values. The expected ...

You can access the real data type of interface with Type Assertion. interfaceVariable.(DataType) Example of struct MyType which implement interface Subber: package main import ( "fmt" ) type Subber interface { Sub(a, b int) int } type MyType struct { Msg stri...

Debugging takes time and effort. Instead of chasing bugs with a debugger, consider spending more time on making your code better by: Write and run Tests. Python and Django have great builtin testing frameworks - that can be used to test your code much faster than manually with a debugger. Writ...

The non-null assertion operator, !, allows you to assert that an expression isn't null or undefined when the TypeScript compiler can't infer that automatically: type ListNode = { data: number; next?: ListNode; }; function addNext(node: ListNode) { if (node.next === undefined) { nod...