386 lines
11 KiB
JavaScript
386 lines
11 KiB
JavaScript
// # Assert.js
|
|
// A run-time type assertion library for JavaScript. Designed to be used with [Traceur](https://github.com/google/traceur-compiler).
|
|
|
|
|
|
// - [Basic Type Check](#basic-type-check)
|
|
// - [Custom Check](#custom-check)
|
|
// - [Primitive Values](#primitive-values)
|
|
// - [Describing more complex types](#describing-more-complex-types)
|
|
// - [assert.arrayOf](#assert-arrayof)
|
|
// - [assert.structure](#assert-structure)
|
|
// - [Integrating with Traceur](#integrating-with-traceur)
|
|
|
|
// Note: `assert` gets automatically included by traceur!
|
|
|
|
export function main() {
|
|
|
|
// ## Basic Type Check
|
|
// By default, `instanceof` is used to check the type.
|
|
//
|
|
// Note that you can use `assert.type()` in unit tests or anywhere in your code.
|
|
// Most of the time, you will use it with Traceur.
|
|
// Jump to the [Traceur section](#integrating-with-traceur) to see an example of that.
|
|
describe('basic type check', function() {
|
|
|
|
class Type {}
|
|
|
|
it('should pass', function() {
|
|
assert.type(new Type(), Type);
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => assert.type(123, Type))
|
|
.toThrowError('Expected an instance of Type, got 123!');
|
|
});
|
|
|
|
|
|
it('should allow null', function() {
|
|
assert.type(null, Type);
|
|
});
|
|
});
|
|
|
|
|
|
|
|
// ## Custom Check
|
|
// Often, `instanceof` is not flexible enough.
|
|
// In that case, your type can define its own `assert` method which will be used instead.
|
|
//
|
|
// See [Describing More Complex Types](#describing-more-complex-types) for examples how to
|
|
// define custom checks using `assert.define()`.
|
|
describe('custom check', function() {
|
|
|
|
class Type {}
|
|
|
|
// the basic check can just return true/false, without specifying any reason
|
|
it('should pass when returns true', function() {
|
|
Type.assert = function(value) {
|
|
return true;
|
|
};
|
|
|
|
assert.type({}, Type);
|
|
});
|
|
|
|
|
|
it('should fail when returns false', function() {
|
|
Type.assert = function(value) {
|
|
return false;
|
|
};
|
|
|
|
expect(() => assert.type({}, Type))
|
|
.toThrowError('Expected an instance of Type, got {}!');
|
|
});
|
|
|
|
|
|
// Using `assert.fail()` allows to report even multiple errors.
|
|
it('should fail when calls assert.fail()', function() {
|
|
Type.assert = function(value) {
|
|
assert.fail('not smart enough');
|
|
assert.fail('not blue enough');
|
|
};
|
|
|
|
expect(() => assert.type({}, Type))
|
|
.toThrowError('Expected an instance of Type, got {}!\n' +
|
|
' - not smart enough\n' +
|
|
' - not blue enough');
|
|
});
|
|
|
|
|
|
it('should fail when throws an exception', function() {
|
|
Type.assert = function(value) {
|
|
throw new Error('not long enough');
|
|
};
|
|
|
|
expect(function() {
|
|
assert.type(12345, Type);
|
|
}).toThrowError('Expected an instance of Type, got 12345!\n' +
|
|
' - not long enough');
|
|
});
|
|
});
|
|
|
|
|
|
|
|
// ## Primitive Values
|
|
// You don't want to check primitive values (such as strings, numbers, or booleans) using `typeof` rather than
|
|
// `instanceof`.
|
|
//
|
|
// Again, you probably won't write this code and rather use Traceur to do it for you, simply based on type annotations.
|
|
describe('primitive value check', function() {
|
|
var primitive = $traceurRuntime.type;
|
|
|
|
describe('string', function() {
|
|
|
|
it('should pass', function() {
|
|
assert.type('xxx', primitive.string);
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => assert.type(12345, primitive.string))
|
|
.toThrowError('Expected an instance of string, got 12345!');
|
|
});
|
|
|
|
it('should allow null', function() {
|
|
assert.type(null, primitive.string);
|
|
});
|
|
});
|
|
|
|
|
|
describe('number', function() {
|
|
|
|
it('should pass', function() {
|
|
assert.type(123, primitive.number);
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => assert.type(false, primitive.number))
|
|
.toThrowError('Expected an instance of number, got false!');
|
|
});
|
|
|
|
it('should allow null', function() {
|
|
assert.type(null, primitive.number);
|
|
});
|
|
});
|
|
|
|
|
|
describe('boolean', function() {
|
|
|
|
it('should pass', function() {
|
|
expect(assert.type(true, primitive.boolean)).toBe(true);
|
|
expect(assert.type(false, primitive.boolean)).toBe(false);
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => assert.type(123, primitive.boolean))
|
|
.toThrowError('Expected an instance of boolean, got 123!');
|
|
});
|
|
|
|
it('should allow null', function() {
|
|
assert.type(null, primitive.boolean);
|
|
});
|
|
});
|
|
});
|
|
|
|
|
|
// ## Describing more complex types
|
|
//
|
|
// Often, a simple type check using `instanceof` or `typeof` is not enough.
|
|
// That's why you can define custom checks using this DSL.
|
|
// The goal was to make them easy to compose and as descriptive as possible.
|
|
// Of course you can write your own DSL on the top of this.
|
|
describe('define', function() {
|
|
|
|
// If the first argument to `assert.define()` is a type (function), it will define `assert` method on that function.
|
|
//
|
|
// In this example, being a type of Type means being a either a function or object.
|
|
it('should define assert for an existing type', function() {
|
|
class Type {}
|
|
|
|
assert.define(Type, function(value) {
|
|
assert(value).is(Function, Object);
|
|
});
|
|
|
|
assert.type({}, Type);
|
|
assert.type(function() {}, Type);
|
|
expect(() => assert.type('str', Type))
|
|
.toThrowError('Expected an instance of Type, got "str"!\n' +
|
|
' - "str" is not instance of Function\n' +
|
|
' - "str" is not instance of Object');
|
|
});
|
|
|
|
|
|
// If the first argument to `assert.define()` is a string,
|
|
// it will create an interface - basically an empty class with `assert` method.
|
|
it('should define an interface', function() {
|
|
var User = assert.define('MyUser', function(user) {
|
|
assert(user).is(Object);
|
|
});
|
|
|
|
assert.type({}, User);
|
|
expect(() => assert.type(12345, User))
|
|
.toThrowError('Expected an instance of MyUser, got 12345!\n' +
|
|
' - 12345 is not instance of Object');
|
|
});
|
|
|
|
|
|
// Here are a couple of more APIs to describe your custom types...
|
|
//
|
|
// ### assert.arrayOf
|
|
// Checks if the value is an array and if so, it checks whether all the items are one the given types.
|
|
// These types can be composed types, not just simple ones.
|
|
describe('arrayOf', function() {
|
|
|
|
var Titles = assert.define('ListOfTitles', function(value) {
|
|
assert(value).is(assert.arrayOf(assert.string, assert.number));
|
|
});
|
|
|
|
it('should pass', function () {
|
|
assert.type(['one', 55, 'two'], Titles);
|
|
});
|
|
|
|
|
|
it('should fail when non-array given', function () {
|
|
expect(() => assert.type('foo', Titles))
|
|
.toThrowError('Expected an instance of ListOfTitles, got "foo"!\n' +
|
|
' - "foo" is not instance of array of string/number\n' +
|
|
' - "foo" is not instance of Array');
|
|
});
|
|
|
|
|
|
it('should fail when an invalid item in the array', function () {
|
|
expect(() => assert.type(['aaa', true], Titles))
|
|
.toThrowError('Expected an instance of ListOfTitles, got ["aaa", true]!\n' +
|
|
' - ["aaa", true] is not instance of array of string/number\n' +
|
|
' - true is not instance of string\n' +
|
|
' - true is not instance of number');
|
|
});
|
|
});
|
|
|
|
|
|
// ### assert.structure
|
|
// Similar to `assert.arrayOf` which checks a content of an array,
|
|
// `assert.structure` checks if the value is an object with specific properties.
|
|
describe('structure', function() {
|
|
|
|
var User = assert.define('MyUser', function(value) {
|
|
assert(value).is(assert.structure({
|
|
name: assert.string,
|
|
age: assert.number
|
|
}));
|
|
});
|
|
|
|
it('should pass', function () {
|
|
assert.type({name: 'Vojta', age: 28}, User);
|
|
});
|
|
|
|
|
|
it('should fail when non-object given', function () {
|
|
expect(() => assert.type(123, User))
|
|
.toThrowError('Expected an instance of MyUser, got 123!\n' +
|
|
' - 123 is not instance of object with properties name, age\n' +
|
|
' - 123 is not instance of Object');
|
|
});
|
|
|
|
|
|
it('should fail when an invalid property', function () {
|
|
expect(() => assert.type({name: 'Vojta', age: true}, User))
|
|
.toThrowError('Expected an instance of MyUser, got {name: "Vojta", age: true}!\n' +
|
|
' - {name: "Vojta", age: true} is not instance of object with properties name, age\n' +
|
|
' - true is not instance of number');
|
|
});
|
|
});
|
|
});
|
|
|
|
|
|
|
|
// ## Integrating with Traceur
|
|
//
|
|
// Manually calling `assert.type()` in your code is cumbersome. Most of the time, you'll want to
|
|
// have Traceur add the calls to `assert.type()` to your code based on type annotations.
|
|
//
|
|
// This has several advantages:
|
|
// - it's shorter and nicer,
|
|
// - you can easily ignore it when generating production code.
|
|
//
|
|
// You'll need to run Traceur with `--types=true --type-assertions=true --type-assertion-module="path/to/assert"`.
|
|
describe('Traceur', function() {
|
|
|
|
describe('arguments', function() {
|
|
|
|
function reverse(str: string) {
|
|
return str ? reverse(str.substring(1)) + str[0] : ''
|
|
}
|
|
|
|
it('should pass', function() {
|
|
expect(reverse('angular')).toBe('ralugna');
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => reverse(123))
|
|
.toThrowError('Invalid arguments given!\n' +
|
|
' - 1st argument has to be an instance of string, got 123');
|
|
});
|
|
});
|
|
|
|
|
|
describe('return value', function() {
|
|
|
|
function foo(bar): number {
|
|
return bar;
|
|
}
|
|
|
|
it('should pass', function() {
|
|
expect(foo(123)).toBe(123);
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => foo('bar'))
|
|
.toThrowError('Expected to return an instance of number, got "bar"!');
|
|
});
|
|
});
|
|
|
|
|
|
describe('variables', function() {
|
|
|
|
it('should pass', function() {
|
|
var count:number = 1;
|
|
});
|
|
|
|
|
|
it('should fail', function() {
|
|
expect(() => {
|
|
var count: number = true;
|
|
}).toThrowError('Expected an instance of number, got true!');
|
|
});
|
|
});
|
|
|
|
|
|
describe('void', function() {
|
|
function foo(bar): void {
|
|
return bar;
|
|
}
|
|
|
|
it('should pass when not defined', function() {
|
|
function nonReturn(): void {}
|
|
function returnNothing(): void { return; }
|
|
function returnUndefined(): void { return undefined; }
|
|
|
|
foo();
|
|
foo(undefined);
|
|
nonReturn();
|
|
returnNothing();
|
|
returnUndefined();
|
|
});
|
|
|
|
|
|
it('should fail when a value returned', function() {
|
|
expect(() => foo('bar'))
|
|
.toThrowError('Expected to return an instance of void, got "bar"!');
|
|
});
|
|
|
|
|
|
it('should fail when null returned', function() {
|
|
expect(() => foo(null))
|
|
.toThrowError('Expected to return an instance of void, got null!');
|
|
});
|
|
});
|
|
|
|
|
|
describe('generics', function() {
|
|
|
|
it('should pass', function() {
|
|
var list:Array<string> = [];
|
|
});
|
|
|
|
// TODO(tbosch): add assertions based on generics to rtts_assert
|
|
|
|
});
|
|
|
|
});
|
|
|
|
}
|