gnome-shell/tests/unit/injectionManager.js
Florian Müllner f70a75a905 extensionUtils: Add InjectionManager
It is fairly common for extensions to monkey-patch existing
classes. Add a small helper class that makes this a tad bit
more convenient.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2809>
2023-08-05 12:34:41 +02:00

94 lines
2.1 KiB
JavaScript

const JsUnit = imports.jsUnit;
import '../../js/ui/environment.js';
import {InjectionManager} from '../../js/extensions/extension.js';
class Object1 {
count = 0;
getNumber() {
return 42;
}
getCount() {
return ++this.count;
}
}
/**
* @param {object} object to modify
*/
function addInjections(object) {
// extend original method
injectionManager.overrideMethod(
object, 'getNumber', originalMethod => {
return function () {
// eslint-disable-next-line no-invalid-this
const num = originalMethod.call(this);
return 2 * num;
};
});
// override original method
injectionManager.overrideMethod(
object, 'getCount', () => {
return function () {
return 42;
};
});
// inject new method
injectionManager.overrideMethod(
object, 'getOtherNumber', () => {
return function () {
return 42;
};
});
}
const injectionManager = new InjectionManager();
let obj;
// Prototype injections
addInjections(Object1.prototype);
obj = new Object1();
// new obj is modified
JsUnit.assertEquals(obj.getNumber(), 84);
JsUnit.assertEquals(obj.getCount(), 42);
JsUnit.assertEquals(obj.count, 0);
JsUnit.assertEquals(obj.getOtherNumber(), 42);
injectionManager.clear();
obj = new Object1();
// new obj is unmodified
JsUnit.assertEquals(obj.getNumber(), 42);
JsUnit.assertEquals(obj.getCount(), obj.count);
JsUnit.assert(obj.count > 0);
JsUnit.assertRaises(() => obj.getOtherNumber());
// instance injections
addInjections(obj);
// obj is now modified
JsUnit.assertEquals(obj.getNumber(), 84);
JsUnit.assertEquals(obj.getCount(), 42);
JsUnit.assertEquals(obj.count, 1);
JsUnit.assertEquals(obj.getOtherNumber(), 42);
injectionManager.restoreMethod(obj, 'getNumber');
JsUnit.assertEquals(obj.getNumber(), 42);
injectionManager.clear();
// obj is unmodified again
JsUnit.assertEquals(obj.getNumber(), 42);
JsUnit.assertEquals(obj.getCount(), obj.count);
JsUnit.assert(obj.count > 0);
JsUnit.assertRaises(() => obj.getOtherNumber());