Chai assert

Cypress bundles the popular Chai assertion library, chai assert, as well as helpful extensions for Sinon and jQuerybringing you dozens of powerful assertions for free.

For more information or to download plugins, view the documentation. Chai is an assertion library , similar to Node's built-in assert. It makes testing much easier by giving you lots of assertions you can run against your code. To install it, type:. You can also use it within the browser; install via npm and use the chai. For example:.

Chai assert

The assert style is very similar to node. Of the three style options, assert is the only one that is not chainable. Check out the Style Guide for a comparison. Throw a failure. Asserts non-strict inequality! Asserts strict inequality! Asserts that actual is deeply equal to expected. Assert that actual is not deeply equal to expected. Asserts that value is undefined. Asserts that value is not undefined. Asserts that value is not a function.

Asserts that object has all and only all of the keys provided. Order is not taken into account.

The assert style is very similar to node. Of the three style options, assert is the only one that is not chainable. Check out the Style Guide for a comparison. Throw a failure. Asserts that object is truthy.

Chai is one of the most popular assertion libraries when writing test suites with Mocha. This article assumes you are already acquainted with Mocha, so check out our introduction to Mocha first. Chai supports 3 different assertion styles : expect , should , and assert. Here's how you would write a sum. The goal of Chai's expect and should interfaces is to allow you to write assertions in a way that mimics natural language. For example, to assert that a value is an array that includes '3', you would write:. The Chai docs have a complete list of language chains and comparisons. The expect API is chainable and very expressive. Advanced Chai users can often write all their assertions with one expect chain. Often you don't want to assert that two objects are exactly deep equal, but that an object has certain properties set.

Chai assert

The assert style is very similar to node. Of the three style options, assert is the only one that is not chainable. Check out the Style Guide for a comparison. Throw a failure. Asserts that object is truthy. Asserts that object is falsy.

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Can be used to assert the inclusion of a subset of properties in an object while ignoring inherited properties. Sponsor this project opencollective. Asserts value is not an instance of constructor. Asserts that object does not have a property named by property , which can be a string using dot- and bracket-notation for deep reference. Asserts that value is true. Watch the short video "Multiple elements and should 'be. Asserts that value is not undefined. The assertion does not match subclassed objects. Code of conduct. Asserts that subset is included in superset in any order.

The BDD styles are expect and should. Both use the same chainable language to construct assertions, but they differ in the way an assertion is initially constructed.

Compares two values using operator. Asserts strict inequality! For more information or to download plugins, view the documentation. Assert that actual is not deeply equal to expected. Asserts non-strict inequality! Asserts that value does not match the regular expression regexp. Check out the Style Guide for a comparison. Asserts that object has all of the keys provided but may have more keys not listed. Related Projects. Packages 0 No packages published. Asserts that object is sealed cannot have new properties added to it and its existing properties cannot be removed. Asserts that object does not have a property named by property with value given by value. Watch the short video "Multiple elements and should 'be.