ds4/spec/expression-evaluation/evaluator.spec.ts

90 lines
2.6 KiB
TypeScript

// SPDX-FileCopyrightText: 2022 Johannes Loher
//
// SPDX-License-Identifier: MIT
import { describe, expect, it } from "vitest";
import { defaultEvaluator, Evaluator, mathEvaluator } from "../../src/expression-evaluation/evaluator";
describe("Evaluator", () => {
it("evaluates expressions that only use identifiers according to the given predicate", () => {
// given
const expression = "typeof 'foo' === 'string' ? 42 : null";
// when
const result = defaultEvaluator.evaluate(expression);
// then
expect(result).toEqual(42);
});
it("fails to evaluate expressions that contain identifiers that are not allowed by the predicate", () => {
// given
const expression = "typeof 'foo' === 'string' ? 42 : function (){}";
// when
const evaluate = () => defaultEvaluator.evaluate(expression);
// then
expect(evaluate).toThrowError("'function' is not an allowed identifier.");
});
it("fails to evaluate expressions that contain invalid tokens", () => {
// given
const expression = "1;";
// when
const evaluate = () => defaultEvaluator.evaluate(expression);
// then
expect(evaluate).toThrowError("Invalid or unexpected token (1)");
});
it("fails to evaluate expressions that contain arrow functions", () => {
// given
const expression = "(() => 1)()";
// when
const evaluate = () => defaultEvaluator.evaluate(expression);
// then
expect(evaluate).toThrowError("Invalid or unexpected token (4)");
});
it("makes the given context available", () => {
// given
const context = { floor: Math.floor };
const evaluator = new Evaluator({ context });
const expression = "floor(0.5)";
// when
const result = evaluator.evaluate(expression);
// then
expect(result).toEqual(0);
});
describe("mathEvaluator", () => {
it("makes the given context available", () => {
// given
const expression = "sqrt(sin(PI))";
// when
const result = mathEvaluator.evaluate(expression);
// then
expect(result).toEqual(Math.sqrt(Math.sin(Math.PI)));
});
it("does not give acces to the function constructor", () => {
// given
const expression = "sqrt.constructor";
// when
const evaluate = () => mathEvaluator.evaluate(expression);
// then
expect(evaluate).toThrowError("'constructor' is not an allowed identifier.");
});
});
});