mathjs/test/expression/parser.test.js

112 lines
3.1 KiB
JavaScript

// test parser
var assert = require('assert'),
approx = require('../../tools/approx.js'),
math = require('../../index.js');
describe('parser', function() {
it ('should create a parser', function () {
var parser = math.parser();
assert.ok(parser instanceof math.expression.Parser);
});
it ('should parse an expression', function () {
var parser = math.parser();
var node = parser.parse('2 + 3');
assert.ok(node instanceof math.expression.node.Node);
assert.equal(node.eval(), 5);
});
it ('should evaluate an expression', function () {
var parser = math.parser();
var result = parser.eval('2 + 3');
assert.equal(result, 5);
});
it ('should get variables from the parsers namespace ', function () {
var parser = math.parser();
parser.eval('a = 3');
parser.eval('b = a + 2');
assert.equal(parser.eval('a'), 3);
assert.equal(parser.eval('b'), 5);
assert.equal(parser.get('a'), 3);
assert.equal(parser.get('b'), 5);
});
it ('should return null when getting a non existing variable', function () {
var parser = math.parser();
assert.equal(parser.get('non_existing_variable'), null);
});
it ('should set variables in the parsers namespace ', function () {
var parser = math.parser();
assert.equal(parser.set('a', 3), 3);
assert.equal(parser.eval('a'), 3);
assert.equal(parser.eval('a + 2'), 5);
// adjust variable
assert.equal(parser.eval('a = a + 2'), 5);
assert.equal(parser.eval('a'), 5);
assert.equal(parser.get('a'), 5);
assert.equal(parser.set('a', parser.get('a') - 4), 1);
assert.equal(parser.eval('a'), 1);
});
it ('should remove a variable from the parsers namespace ', function () {
var parser = math.parser();
assert.equal(parser.set('qq', 3), 3);
assert.equal(parser.eval('qq'), 3);
assert.equal(parser.get('qq'), 3);
parser.remove('qq');
assert.equal(parser.get('qq'), null);
assert.throws(function () {parser.eval('qq')});
assert.equal(parser.eval('ww = 5'), 5);
assert.equal(parser.get('ww'), 5);
parser.remove('ww');
assert.equal(parser.get('ww'), null);
assert.throws(function () {parser.eval('ww')});
});
it ('should clear the parsers namespace ', function () {
var parser = math.parser();
assert.equal(parser.eval('xx = yy = zz = 5'), 5);
assert.equal(parser.set('pi', 'oops'), 'oops');
assert.equal(parser.get('xx'), 5);
assert.equal(parser.get('yy'), 5);
assert.equal(parser.get('zz'), 5);
assert.equal(parser.get('pi'), 'oops');
assert.equal(parser.eval('xx'), 5);
assert.equal(parser.eval('yy'), 5);
assert.equal(parser.eval('zz'), 5);
assert.equal(parser.eval('pi'), 'oops');
parser.clear();
assert.equal(parser.get('xx'), null);
assert.equal(parser.get('yy'), null);
assert.equal(parser.get('zz'), null);
approx.equal(parser.get('pi'), Math.PI);
assert.throws(function () {parser.eval('xx')});
assert.throws(function () {parser.eval('yy')});
assert.throws(function () {parser.eval('zz')});
assert.equal(parser.eval('pi'), Math.PI);
});
});