Add unit tests

[ljvmiranda921]

The main challenge here is to mock the bigquery client. Still not sure how this will all work, but we should have atleast good test coverage for this project.

[marksteve]

We can use https://www.gaia-gis.it/fossil/libspatialite/index to test SQL queries without querying BQ directly

[ljvmiranda921]

I can take a look at this this weekend! So main idea is to create test fixtures from a SQLite DB

[ljvmiranda921]

Some notes:

• Create a SQLite source test database by loading Philippine shapefiles from Geofrabrik. Check this tutorial. Although I don't think we'll need the whole thing, especially if we're going to commit this? Maybe just get via wget instead
• The same goes for a test database of points
• https://www.gaia-gis.it/gaia-sins/BLOB-Geometry.html
• Use AsText
• Just load the CSV with WKT columns into the db

import sqlite3
conn = sqlite3.connect('test_source.sqlite')
conn.enable_load_extension(True)

try:
    conn.load_extension('mod_spatialite.so')
except OperationalError:
    conn.load_extension('libspatialite.so')

cursor = conn.cursor()
cursor.execute(QUERY)

More info on mod_spatialite.so