Chai.js
Chinotto: Custom assertions forCompilation of useful Chai assertions that I've written over time,
migrated from the test-suites of various projects (atom-mocha
in particular).
“Uh, why did you name thi-”
Because if Chai and Mocha proved anything, it's that beverages make memorable library names. Also, I enjoy Chinotto and the name on NPM was available, so I took it. Superalo.
Usage
-
Add
chinotto
to your project'sdevDependencies
:$ npm install --save-dev chinotto
-
Then call the
register()
function it exports:require("chinotto").register();
This automatically registers every available extension with Chai, which are used like any other BDD-style assertion:
expect(__filename).to.be.a.file.and.to.existOnDisk; __dirname.should.be.a.file.and.equalPath(__dirname + "/");
Alternatively, you can just import
chinotto/register
instead. This callsregister()
for you automatically, and makesChinotto
globally available:require("chinotto/register"); // Define a hypothetical extension to check modification status: global.Chinotto.defineAssertion("modified", (subject, expected) => [subject.isModified(), "to be modified"]); // Usage: expect("/some/edited/file").to.be.modified; expect("/unedited/file").not.to.be.modified;
API reference
Extension list
Exports
chai
:Object
— Reference to the Chai module used by Chinotto.methods
:Map
— Handler functions for assertion methods, keyed by name(s)properties
:Map
— Handler functions for assertion properties, keyed by name(s)
The remaining exports are detailed under Utils:
Methods
class()
/classes()
Check if an HTMLElement
contains one or more CSS classes.
Parameter | Type | Attributes | Description |
---|---|---|---|
expected |
String , Array.<String> |
Variadic | An array or whitespace-delimited list of CSS class-names |
Example:
document.body.should.have.class("content");
expect($(".btn.large")).to.have.classes("btn", "large");
equalPath()
Assert that two filesystem paths are logically the same.
Parameter | Type |
---|---|
target |
String |
Example:
"/bin".should.equalPath("/bin/");
"/bin/../bin".should.equalPath("/bin");
hardLink()
/hardLinkOf()
Assert that two files have the same inode and device number.
Parameter | Type |
---|---|
target |
String |
Example:
"/a/huge/file".should.have.hardLink("/same/huge/file");
expect("huge.file").to.be.hardLinkOf("also.huge");
pointTo()
/pointingTo()
Assert that a symbolic link points to the specified file.
Parameter | Type |
---|---|
target |
String |
Example:
"/tmp".should.be.a.symlink.pointingTo("/private/tmp");
Properties
.drawn
Assert that an HTMLElement
is rendered in the DOM tree.
Example:
document.body.should.be.drawn;
document.head.should.not.be.drawn;
.focus
Assert that an HTMLElement
has user focus, or contains something which does.
Example:
document.activeElement.should.have.focus;
document.createElement("div").should.not.have.focus;
.existOnDisk
/.existsOnDisk
Assert that a file exists in the filesystem.
Example:
"/bin/sh".should.existOnDisk
"<>:*?\0".should.not.existOnDisk
.file
/.regularFile
Assert that subject is a path pointing to a regular file.
Example:
"/bin/sh".should.be.a.file
"/bin".should.not.be.a.file
.directory
Assert that subject is a path pointing to a directory.
Example:
"/bin".should.be.a.directory
"/bin/sh".should.not.be.a.directory
.symlink
/.symbolicLink
Assert that subject is a path pointing to a symbolic link.
Example:
"/usr/local/bin/node".should.be.a.symlink
.device
/.deviceFile
Assert that subject is a path pointing to a device file.
“Device file” refers to either a character device or a block device, making
this assertion preferable to blockDevice
and characterDevice
for cross-platform testing.
Example:
"/dev/zero".should.be.a.device;
.blockDevice
Assert that subject is a path pointing to a block device.
Example:
"/dev/disk0s1".should.be.a.blockDevice
.characterDevice
/.charDevice
Assert that subject is a path pointing to a character device.
Example:
"/dev/null".should.be.a.characterDevice
.fifo
/.namedPipe
Assert that subject is a path pointing to a FIFO (named pipe).
Example:
"/tmp/154B17E1-2BF7_IN".should.be.a.fifo
.door
Assert that subject is a path pointing to a door.
Example:
"/system/volatile/syslog_door".should.be.a.door
.socket
Assert that subject is a path pointing to a socket.
Example:
"/run/systemd/private".should.be.a.socket
Utils
addMethod()
Variant of chai.Assertion.addMethod
that supports plugin aliases.
If the property already exists on the prototype, it will not be overwritten.
To redefine existing methods and prototypes, use chai.util.addMethod
or chai.util.overwriteMethod
.
Parameter | Type |
---|---|
names |
String , Array.<String> |
fn |
function |
Example:
addMethod(["pointTo", "pointingTo"], function(target){ … });
addProperty()
Variant of chai.Assertion.addProperty
that supports plugin aliases.
Parameter | Type |
---|---|
names |
String , Array.<String> |
fn |
function |
Example:
addProperty(["coloured", "colored"], fn);
defineAssertion()
Variant of defineAssertions
that defines only one assertion.
Parameter | Type |
---|---|
names |
String , Array.<String> |
handler |
function |
defineAssertions()
Wrapper for defining simple custom Chai assertions.
Parameter | Type |
---|---|
spec |
Object |
Example:
<caption>Defining a "colour" assertion</caption>
// Typical definition:
defineAssertions({
["colour, coloured"](subject, expected){
const actual = subject.colour;
this.assert(
actual === expected,
"expected #{this} to be coloured #{exp}",
"expected #{this} not to be coloured #{exp}",
expected,
actual
);
},
});
// Usage:
expect({colour: 0xFF0000}).to.have.colour(0xFF0000);
expect({colour: "red"}).not.to.be.coloured("green");
<caption>Shorthand for the above</caption>
defineAssertions({
["colour, coloured"](subject, expected){
return [
subject.colour === expected,
"to be coloured #{exp}",
];
},
});
register()
Register every available Chai extension.
Example:
import Chinotto from "./lib/index.mjs";
Chinotto.register();