justo-dummy

A test dummy library.

Proudly made with ♥ in Valencia, Spain, EU.

Test doubles

A test double is an object that represents other, used to perform in unit testings. There are several types of test doubles:

• Test dummies. Test double that responds to calls with no action.
• Test stubs. Test double that responds to calls with predefined responses.
• Test spies. Test double that monitors the calls to an object.

Install

npm install justo-dummy

Test dummies

A test dummy is an object that when it is call, it always returns undefined. We can create function dummies and object dummies.

dummy()

To create a test dummy, we must use the dummy() function:

const dummy = require("justo-dummy");

Function dummy

A function dummy does nothing. When it is called, it always returns undefined. The dummy() overload to use is:

dummy() : function

Example:

var fn = dummy();

Object dummy

An object dummy is an object whose members always return undefined. The dummy() overload to use is:

dummy(obj : object) : object
dummy(obj : object, member : string) : object
dummy(obj : object, members: string[]) : object

The obj is the object to double and the member and members parameters are the members for doubling.

Example:

user = dummy(new User("user01", "password"));
user = dummy(new User("user01", "password"), "changePassword()");
user = dummy(new User("user01", "password"), ["changePassword()"]);

API dummy

The object returned by the dummy() contains a property, dummy, which is used to configure the object dummy.

Configuring responses

The object dummies can configure responses for attributes and methods. This configuration is very easy. We must use the dummy property of the object dummy.

Configuring methods

To configure a method response, we will use the respond() method of the API object:

respond(name : string)

The name parameter is the method name to double followed by ().

Example:

var calcul = dummy({});

calcul.dummy.respond("sum()");
calcul.dummy.respond("sub()");

Once we have added a response, we will see the method in the object.

Configuring attributes

To configure an attribute response, we will use the same signature of the respond() method:

respond(name : string)

But now, the name parameter is the attribute name prefixed by @.

Example:

var list = dummy({});

list.dummy.respond("@length");

Once we have added a response, we will see the attribute in the object.