Ghost/test/unit/frontend/helpers/match.test.js
Hannah Wolfe fbc23459fc
Added full SafeString handling to match helper
refs: https://github.com/TryGhost/Team/issues/759

- No matter what, a handlebars helper outputs a string. So if you return true, you'll always get 'true'.
- SafeStrings are handlebars's way of passing around a string whilst also maintaining a record of the original value e.g. new SafeString(true) results in {string: true}
- We need this for the match helper, so that we know when doing a comparison that we're meant to be comparing against a boolean true, not a string true
- Therefore, we need to putput SafeStrings, but also process them when passed in

The logic
- Figuring out the correct logic here has been a little tricky but essentially:
  - {{match safestring}} with a single arg, will return true for any truthy value
  - {{match safestring "=" true}} does a direct comparison with the original value of the safe string, so if it was a boolean true, the match will be true else false
  - {{match (match something) "=" true}} will therefore work for any level of nesting
  - this can result in slightly inconsistent results, but feels correct and documentable

This is documented extensively through the test cases
2021-10-14 16:29:41 +01:00

240 lines
11 KiB
JavaScript

const should = require('should');
const sinon = require('sinon');
const _ = require('lodash');
const matchHelper = require('../../../../core/frontend/helpers/match');
const titleHelper = require('../../../../core/frontend/helpers/title');
const labs = require('../../../../core/shared/labs');
const handlebars = require('../../../../core/frontend/services/theme-engine/engine').handlebars;
const {SafeString} = require('express-hbs');
describe('Match helper', function () {
before(function () {
handlebars.registerHelper('match', matchHelper);
handlebars.registerHelper('title', titleHelper);
});
afterEach(function () {
sinon.restore();
});
beforeEach(function () {
sinon.stub(labs, 'isSet').returns(true);
});
function shouldCompileToExpected(templateString, hash, expected) {
const template = handlebars.compile(templateString);
const result = template(hash);
result.should.eql(expected);
}
/**
* Run tests takes a list of tests & a data hash in the form of two objects
* The key is the template string, the value is the expected value when the template is compiled with the given hash object
*
* @param {object} tests
* @param {object} hash
*/
function runTests(tests, hash) {
_.each(tests, (expectedString, templateString) => {
it(`${templateString} resolves to '${expectedString}'`, function () {
shouldCompileToExpected(templateString, hash, expectedString);
});
});
}
// The match helper, by default, is an inline helper that returns either true or false (as a string) for any given set of arguments.
// In the first instance, the unit tests should check various combinations of arguments to ensure we get the right answer
describe('{{match}} (inline)', function () {
const hash = {
truthy_bool: true,
falsy_bool: false,
zero: 0,
one: 1,
string: 'Hello world',
title: 'The Title',
string_true: 'true',
string_false: 'false',
safestring_string_true: new SafeString('true'),
safestring_string_false: new SafeString('false'),
safestring_bool_true: new SafeString(true),
safestring_bool_false: new SafeString(false),
five: 5,
string_five: '5',
empty: '',
null: null,
object: {
foo: 'foo',
bar: 'bar'
}
};
describe('Basic values', function () {
runTests({
'{{match truthy_bool}}': 'true',
'{{match falsy_bool}}': 'false',
'{{match one}}': 'true',
'{{match zero}}': 'false',
'{{match string}}': 'true',
'{{match string_true}}': 'true',
'{{match string_false}}': 'true',
'{{match safestring_string_true}}': 'true',
'{{match safestring_string_false}}': 'true',
'{{match safestring_bool_true}}': 'true',
'{{match safestring_bool_false}}': 'false',
'{{match empty}}': 'false',
'{{match null}}': 'false',
'{{match undefined}}': 'false',
'{{match unknown}}': 'false',
'{{match object}}': 'true',
'{{match (title)}}': 'true',
// Zero works if includeZero is set
'{{match zero includeZero=true}}': 'true',
// Nesting the helper should still resolve correctly
'{{match (match truthy_bool)}}': 'true',
'{{match (match falsy_bool)}}': 'false'
}, hash);
});
// @TODO: Implement Implicit Equals
// describe('Implicit Equals', function () {
// runTests({
// '{{match string "Hello world"}}': 'true',
// '{{match string "Hello world!"}}': 'false',
// }, hash);
// });
describe('Explicit Equals', function () {
runTests({
'{{match string "=" "Hello world"}}': 'true',
'{{match string "=" "Hello world!"}}': 'false',
'{{match string_true "=" "true"}}': 'true',
'{{match string_true "=" true}}': 'false',
'{{match string_false "=" "false"}}': 'true',
'{{match string_false "=" false}}': 'false',
'{{match safestring_string_true "=" "true"}}': 'true',
'{{match safestring_string_true "=" true}}': 'false',
'{{match safestring_string_false "=" "false"}}': 'true',
'{{match safestring_string_false "=" false}}': 'false',
'{{match safestring_bool_true "=" "true"}}': 'false',
'{{match safestring_bool_true "=" true}}': 'true',
'{{match safestring_bool_false "=" "false"}}': 'false',
'{{match safestring_bool_false "=" false}}': 'true',
'{{match truthy_bool "=" true}}': 'true',
'{{match truthy_bool "=" false}}': 'false',
'{{match falsy_bool "=" false}}': 'true',
'{{match falsy_bool "=" true}}': 'false',
'{{match one "=" 1}}': 'true',
'{{match one "=" "1"}}': 'false',
'{{match zero "=" 0}}': 'true',
'{{match zero "=" "0"}}': 'false',
'{{match (title) "=" "The Title"}}': 'true',
'{{match (title) "=" "The Title!"}}': 'false'
}, hash);
});
describe('Explicit Not Equals', function () {
runTests({
'{{match string "!=" "Hello world"}}': 'false',
'{{match string "!=" "Hello world!"}}': 'true',
'{{match string_true "!=" true}}': 'true',
'{{match string_true "!=" "true"}}': 'false',
'{{match string_false "!=" false}}': 'true',
'{{match string_false "!=" "false"}}': 'false',
'{{match safestring_string_true "!=" "true"}}': 'false',
'{{match safestring_string_true "!=" true}}': 'true',
'{{match safestring_string_false "!=" "false"}}': 'false',
'{{match safestring_string_false "!=" false}}': 'true',
'{{match safestring_bool_true "!=" "true"}}': 'true',
'{{match safestring_bool_true "!=" true}}': 'false',
'{{match safestring_bool_false "!=" "false"}}': 'true',
'{{match safestring_bool_false "!=" false}}': 'false',
'{{match truthy_bool "!=" true}}': 'false',
'{{match truthy_bool "!=" false}}': 'true',
'{{match falsy_bool "!=" false}}': 'false',
'{{match falsy_bool "!=" true}}': 'true',
'{{match one "!=" 1}}': 'false',
'{{match one "!=" "1"}}': 'true',
'{{match zero "!=" 0}}': 'false',
'{{match zero "!=" "0"}}': 'true',
'{{match (title) "!=" "The Title"}}': 'false',
'{{match (title) "!=" "The Title!"}}': 'true'
}, hash);
});
// SafeStrings represent the original value as an object for example:
// SafeString { string: true } vs SafeString { string: 'true' }
// allows us to know if the original value was a boolean or a string
// These tests make sure that we can compare to the _originaL_ value
// But that we don't start allowing weird things like boolean true being equal to string true
describe('SafeString behaviour makes sense(ish)', function () {
runTests({
// Title equals true value = true
'{{match (match title "=" "The Title") "=" "true"}}': 'false',
'{{match (match title "=" "The Title") "=" true}}': 'true',
'{{match (match title "=" "The Title")}}': 'true',
// With title as a helper that also outputs a SafeString
'{{match (match (title) "=" "The Title") "=" "true"}}': 'false',
'{{match (match (title) "=" "The Title") "=" true}}': 'true',
'{{match (match (title) "=" "The Title")}}': 'true',
// Title equals false value = true
'{{match (match title "=" "The Title!") "=" "false"}}': 'false',
'{{match (match title "=" "The Title!") "=" false}}': 'true',
'{{match (match title "=" "The Title!")}}': 'false',
// With title as a helper that also outputs a SafeString
'{{match (match (title) "=" "The Title!") "=" "false"}}': 'false',
'{{match (match (title) "=" "The Title!") "=" false}}': 'true',
'{{match (match (title) "=" "The Title!")}}': 'false',
// // Reverse, reverse!
// // Title not equals true value = false
'{{match (match title "!=" "The Title") "=" "false"}}': 'false',
'{{match (match title "!=" "The Title") "=" false}}': 'true',
'{{match (match title "!=" "The Title")}}': 'false',
// With title as a helper that also outputs a SafeString
'{{match (match (title) "!=" "The Title") "=" "false"}}': 'false',
'{{match (match (title) "!=" "The Title") "=" false}}': 'true',
'{{match (match (title) "!=" "The Title")}}': 'false',
// Yoda a complex example or two to prove this works
'{{match false "=" (match title "!=" "The Title")}}': 'true',
'{{match "false" "=" (match (title) "!=" "The Title")}}': 'false'
}, {title: 'The Title'});
});
});
// By using match as a block helper, instead of returning true or false, the matching template is executed
// We've already tested all the logic of the matches, for the block helpers we only need to test that the correct template is executed
// These tests are more explicit so it's clear what functionality we're trying to test
describe('{{#match}} (block)', function () {
const templateString = '{{#match title "=" "Hello World"}}case a{{else match title "=" "Hello World!"}}case b{{else}}case c{{/match}}';
it('Executes the first block when match is true', function () {
const title = 'Hello World';
const expected = 'case a';
shouldCompileToExpected(templateString, {title}, expected);
});
it('Executes secondary blocks correctly', function () {
const title = 'Hello World!';
const expected = 'case b';
shouldCompileToExpected(templateString, {title}, expected);
});
it('Executes the else block when match is false', function () {
const title = 'Hello';
const expected = 'case c';
shouldCompileToExpected(templateString, {title}, expected);
});
});
});