"""
This script demonstrates how pytest-runner facilitates
the simple execution of complex tasks with their
dependencies.

Save this file and invoke it
under Python (i.e. ``python test-mongodb-records.py``).

It creates a MongoDB instance, and then runs some
assertions against it.

MongoDB must be installed to a typical location or
available on PATH.

As it uses jaraco.mongodb, set MONGODB_HOME to
specify the MongoDB version to use for the ephemeral
instance.

Running this script will download the necessary
requirements to ./.eggs.
"""

setup_params = dict(
	setup_requires=[
		'pytest_runner',
	],
	tests_require=[
		'pytest',
		'jaraco.mongodb>=3.10',
	],
)

if __name__ == '__main__':
	import sys
	# note that sys.argv[0] is the script name
	opts = ' '.join(sys.argv)
	sys.argv[1:] = ['pytest', '--addopts=' + opts]
	__import__('setuptools').setup(**setup_params)
	raise SystemExit(0)


import random
import itertools

import pytest
from jaraco.mongodb.testing import assert_covered


@pytest.fixture
def docs_in_db(mongodb_instance):
	"""
	Install 100 records with random numbers
	"""
	conn = mongodb_instance.get_connection()
	coll = conn.test_db.test_coll
	coll.drop()
	coll.create_index('number')
	n_records = 100
	for n in itertools.islice(itertools.count(), n_records):
		doc = dict(
			number=random.randint(0, 2**32-1),
			value='some value',
		)
		conn.test_db.test_coll.insert(doc)
	return coll


def test_records(docs_in_db, mongodb_instance):
	"Test 100 records are present and query is covered"
	# load all the numbers to ensure the index is in RAM
	_hint = 'number_1'
	_filter = {'number': {'$gt': 0}}
	_projection = {'number': True, '_id': False}
	cur = docs_in_db.find(filter=_filter, projection=_projection).hint(_hint)
	assert_covered(cur)

	# consume the cursor for good measure
	docs = list(cur)
	assert len(docs) == 100