What does let means in RSpec?

What does let means in RSpec?

let generates a method whose return value is memoized after the first call. This is known as lazy loading because the value is not loaded into memory until the method is called. Here is an example of how let is used within an RSpec test. let will generate a method called thing which returns a new instance of Thing .

What is the difference between let and let RSpec?

You can use let! to force the method’s invocation before each example. The difference between let, and let! is that let! is called in an implicit before block. So the result is evaluated and cached before the it block.

Where can a let Block be defined?

The let method should be called inside an example group. The first argument is the name of a variable to define. The let method is passed a block that computes the value of the variable, and the block will be called if the value of the variable is ever needed. In other words, let variables are lazily evaluated.

What is subject RSpec?

Summary: RSpec’s subject is a special variable that refers to the object being tested. Expectations can be set on it implicitly, which supports one-line examples. It is clear to the reader in some idiomatic cases, but is otherwise hard to understand and should be avoided.

What is assigns RSpec?

assigns relates to the instance variables created within a controller action (and assigned to the view).

What is context in RSpec?

According to the rspec source code, “context” is just a alias method of “describe”, meaning that there is no functional difference between these two methods. However, there is a contextual difference that’ll help to make your tests more understandable by using both of them.

What is RSpec used for?

RSpec is a testing tool for Ruby, created for behavior-driven development (BDD). It is the most frequently used testing library for Ruby in production applications. Even though it has a very rich and powerful DSL (domain-specific language), at its core it is a simple tool which you can start using rather quickly.

How do I name a subject in RSpec?

RSpec lets you declare an “implicit subject” using `subject { … }` which allows for tests like `it { should be_valid }`. If you need to reference your test subject you should explicitly name it using `subject(:your_subject_name) { … }`.

How do I download RSpec?

Installing RSpec Boot up your terminal and punch in gem install rspec to install RSpec. Once that’s done, you can verify your version of RSpec with rspec –version , which will output the current version of each of the packaged gems. Take a minute also to hit rspec –help and look through the various options available.

What are specs in Ruby?

This project contains specs that describe Ruby language syntax, core library classes, and standard library classes. The specs generally serve two purposes: 1) to drive development, and 2) as a verification mechanism. These goal can sometimes be at odds. During development, the code and specs evolve together.

What is Shared_context in RSpec?

Sharing context works in basically the same way. RSpec features a #shared_context method, where you can define variables, instance variables, methods, etc. inside its block that your upcoming tests should share. We can then inject that context into example groups with the, you guessed it, #include_context method.

What is Include_context in RSpec?

include_context . When implicitly including shared contexts via matching metadata, the normal way is to define matching metadata on an example group, in which case the context is included in the entire group. However, you also have the option to include it in an individual example instead.

What RSpec method is used to create an example?

The it Keyword. The word it is another RSpec keyword which is used to define an “Example”. An example is basically a test or a test case. Again, like describe and context, it accepts both class name and string arguments and should be used with a block argument, designated with do/end.

Is RSpec a DSL?

RSpec is a computer domain-specific language (DSL) (particular application domain) testing tool written in the programming language Ruby to test Ruby code. It is a behavior-driven development (BDD) framework which is extensively used in production applications.

What is explicit subject?

matchers and/or extension libraries that hide its use from examples. A named subject improves on the explicit subject by assigning it a contextually. semantic name. Since a named subject is an explicit subject , it still defines the value. that is returned by the subject method in the example scope.

Is RSpec a framework?

Should I use RSpec?

RSpec is way more powerful because it’s far easier to both read and write tests in. It’s also very elegant when using mocks and stubs, a concept which will become extremely useful once you start using them in your tests.

What is It_behaves_like?

RSpec : Shared example group (it_behaves_like , include_examples , shared_examples ) You probably know how to use describe , context , it and specify to clearly communicate one aspect of your code. The nested context provides by it_behaves_like can be used to improve this communication with the reader.