#!/usr/bin/env python

from nose.tools import *
from utilities import execution_path

import os, mapnik

def setup():
    # All of the paths used are relative, if we run the tests
    # from another directory we need to chdir()
    os.chdir(execution_path('.'))

def test_query_tolerance():
    srs = '+init=epsg:4326'
    lyr = mapnik.Layer('test')
    lyr.datasource = mapnik.Shapefile(file='../data/shp/arrows.shp')
    lyr.srs = srs
    _width = 256
    _map = mapnik.Map(_width,_width, srs)
    _map.layers.append(lyr)
    
    # zoom determines tolerance
    _map.zoom_all()
    _map_env = _map.envelope()
    tol = (_map_env.maxx - _map_env.minx) / _width * 3
    # 0.046875 for arrows.shp and zoom_all
    assert tol == 0.046875

    # check point really exists
    x, y = 2.0, 4.0
    features = _map.query_point(0,x,y).features
    assert len(features) == 1

    # check inside tolerance limit
    x = 2.0 + tol * 0.9
    features = _map.query_point(0,x,y).features
    assert len(features) == 1

    # check outside tolerance limit
    x = 2.0 + tol * 1.1
    features = _map.query_point(0,x,y).features
    assert len(features) == 0