import sys, unittest
from django.utils.importlib import import_module

def geo_suite():
    """
    Builds a test suite for the GIS package.  This is not named
    `suite` so it will not interfere with the Django test suite (since
    spatial database tables are required to execute these tests on
    some backends).
    """
    from django.conf import settings
    from django.contrib.gis.geos import GEOS_PREPARE
    from django.contrib.gis.gdal import HAS_GDAL
    from django.contrib.gis.utils import HAS_GEOIP
    from django.contrib.gis.tests.utils import postgis, mysql

    # The test suite.
    s = unittest.TestSuite()

    # Adding the GEOS tests.
    from django.contrib.gis.geos import tests as geos_tests
    s.addTest(geos_tests.suite())

    # Tests that require use of a spatial database (e.g., creation of models)
    test_apps = ['geoapp', 'relatedapp']

    # Tests that do not require setting up and tearing down a spatial database.
    test_suite_names = [
        'test_measure',
        ]

    # Tests applications that require a test spatial db.
    if not mysql:
        test_apps.append('distapp')

    # Only PostGIS using GEOS 3.1+ can support 3D so far.
    if postgis and GEOS_PREPARE:
        test_apps.append('geo3d')

    if HAS_GDAL:
        # These tests require GDAL.
        test_suite_names.extend(['test_spatialrefsys', 'test_geoforms'])
        test_apps.append('layermap')

        # Adding the GDAL tests.
        from django.contrib.gis.gdal import tests as gdal_tests
        s.addTest(gdal_tests.suite())
    else:
        print >>sys.stderr, "GDAL not available - no tests requiring GDAL will be run."

    if HAS_GEOIP and hasattr(settings, 'GEOIP_PATH'):
        test_suite_names.append('test_geoip')

    # Adding the rest of the suites from the modules specified
    # in the `test_suite_names`.
    for suite_name in test_suite_names:
        tsuite = import_module('django.contrib.gis.tests.' + suite_name)
        s.addTest(tsuite.suite())

    return s, test_apps

def run_gis_tests(test_labels, **kwargs):
    """
    Use this routine as the TEST_RUNNER in your settings in order to run the
    GeoDjango test suite.  This must be done as a database superuser for
    PostGIS, so read the docstring in `run_test()` below for more details.
    """
    from django.conf import settings
    from django.db.models import loading
    from django.contrib.gis.tests.utils import mysql

    # Getting initial values.
    old_installed = settings.INSTALLED_APPS
    old_root_urlconf = settings.ROOT_URLCONF

    # Overridding the INSTALLED_APPS with only what we need,
    # to prevent unnecessary database table creation.
    new_installed =  ['django.contrib.sites',
                      'django.contrib.sitemaps',
                      'django.contrib.gis',
                      ]

    # Setting the URLs.
    settings.ROOT_URLCONF = 'django.contrib.gis.tests.urls'

    # Creating the test suite, adding the test models to INSTALLED_APPS, and
    # adding the model test suites to our suite package.
    gis_suite, test_apps = geo_suite()
    for test_model in test_apps:
        module_name = 'django.contrib.gis.tests.%s' % test_model
        if mysql:
            test_module = 'tests_mysql'
        else:
            test_module = 'tests'
        new_installed.append(module_name)

        # Getting the model test suite
        tsuite = import_module(module_name + '.' + test_module)
        gis_suite.addTest(tsuite.suite())

    # Resetting the loaded flag to take into account what we appended to
    # the INSTALLED_APPS (since this routine is invoked through
    # django/core/management, it caches the apps; this ensures that syncdb
    # will see our appended models)
    settings.INSTALLED_APPS = new_installed
    loading.cache.loaded = False

    # Running the tests using the GIS test runner.
    result = run_tests(test_labels, suite=gis_suite, **kwargs)

    # Restoring modified settings.
    settings.INSTALLED_APPS = old_installed
    settings.ROOT_URLCONF = old_root_urlconf

    return result

def run_tests(test_labels, verbosity=1, interactive=True, extra_tests=[], suite=None):
    """
    Set `TEST_RUNNER` in your settings with this routine in order to
    scaffold test spatial databases correctly for your GeoDjango models.
    For more documentation, please consult the following URL:
      http://geodjango.org/docs/testing.html.
    """
    from django.conf import settings
    from django.db import connection
    from django.db.models import get_app, get_apps
    from django.test.simple import build_suite, build_test, reorder_suite, TestCase
    from django.test.utils import setup_test_environment, teardown_test_environment

    # The `create_test_spatial_db` routine abstracts away all the steps needed
    # to properly construct a spatial database for the backend.
    from django.contrib.gis.db.backend import create_test_spatial_db

    # Setting up for testing.
    setup_test_environment()
    settings.DEBUG = False
    old_name = settings.DATABASE_NAME

    # Creating the test spatial database.
    create_test_spatial_db(verbosity=verbosity, autoclobber=not interactive)

    # The suite may be passed in manually, e.g., when we run the GeoDjango test,
    # we want to build it and pass it in due to some customizations.  Otherwise,
    # the normal test suite creation process from `django.test.simple.run_tests`
    # is used to create the test suite.
    if suite is None:
        suite = unittest.TestSuite()
        if test_labels:
            for label in test_labels:
                if '.' in label:
                    suite.addTest(build_test(label))
                else:
                    app = get_app(label)
                    suite.addTest(build_suite(app))
        else:
            for app in get_apps():
                suite.addTest(build_suite(app))

        for test in extra_tests:
            suite.addTest(test)

    suite = reorder_suite(suite, (TestCase,))

    # Executing the tests (including the model tests), and destorying the
    # test database after the tests have completed.
    result = unittest.TextTestRunner(verbosity=verbosity).run(suite)
    connection.creation.destroy_test_db(old_name, verbosity)
    teardown_test_environment()

    # Returning the total failures and errors
    return len(result.failures) + len(result.errors)