var assert = require('assert'),
    error = require('../../../lib/error/index'),
    math = require('../../../index')();

describe('help', function() {

  it('should find documentation for a function by its name', function() {
    var help = math.help('sin');
    assert.ok(help instanceof math.type.Help);
    assert.deepEqual(help.doc, math.expression.docs.sin);
  });

  it('should find documentation for a function by the function itself', function() {
    var help = math.help(math.sin);
    assert.ok(help instanceof math.type.Help);
    assert.deepEqual(help.doc, math.expression.docs.sin);
  });

  it('should throw an error on wrong number of arguments', function() {
    assert.throws(function () {math.help()}, SyntaxError);
    assert.throws(function () {math.help('sin', 2)}, SyntaxError);
  });

  it('should find help from a function name', function() {
    var help = math.help('sin');
    assert(help instanceof math.type.Help);
    assert.equal(help.doc.name, 'sin');
  });

  it('should find help from a function', function() {
    var help = math.help(math.sin);
    assert(help instanceof math.type.Help);
    assert.equal(help.doc.name, 'sin');
  });

  it('should find help from a constant name', function() {
    var help = math.help('pi');
    assert(help instanceof math.type.Help);
    assert.equal(help.doc.name, 'pi');
  });

  it('should find help from a constant', function() {
    var help = math.help(math.pi);
    assert(help instanceof math.type.Help);
    assert.equal(help.doc.name, 'pi');
  });

  it('should throw an error when no help is found', function() {
    assert.throws(function () {math.help(undefined)}, /No documentation found/);
    assert.throws(function () {math.help('nonExistingFunction')}, /No documentation found/);
    assert.throws(function () {math.help('parse')}, /No documentation found/);
  });

});