Bringing back live mongodb tests as optional

README.rst

@@ -401,6 +401,14 @@ To run all tests EXCEPT memory core AND MongoDB core related tests, use:
   pytest -m "not (mongo or memory)"
 
 
+Running MongoDB tests against a live MongoDB instance
+-----------------------------------------------------
+
+**Note to developers:** By default, all MongoDB tests are run against a mocked MongoDB instance, provided by the ``pymongo_inmemory`` package. To run them against a live MongoDB instance, the ``CACHIER_TEST_VS_LIVE_MONGO`` environment variable is set to ``True`` in the ``test`` environment of this repository (and additional environment variables are populated with the appropriate credentials), used by the GitHub Action running tests on every commit and pull request.
+
+Contributers are not expected to run these tests against a live MongoDB instance when developing, as credentials for the testing instance used will NOT be shared, but rather use the testing against the in-memory MongoDB instance as a good proxy. HOWEVER, the tests run against a live MongoDB instance when you submit a PR are the determining tests for deciding whether your code functions correctly against MongoDB.
+
+
 Adding documentation
 --------------------
 

setup.py

@@ -16,7 +16,7 @@
 
 TEST_REQUIRES = [
     # tests and coverages
-    'pytest', 'coverage', 'pytest-cov',
+    'pytest', 'coverage', 'pytest-cov', 'birch',
     # linting and code quality
     'bandit', 'flake8', 'pylint', 'safety',
     # type checking

tests/test_mongo_core.py

@@ -9,25 +9,60 @@
 from datetime import timedelta
 from random import random
 from time import sleep
+from urllib.parse import quote_plus
 
+from birch import Birch
 import pandas as pd
 import pymongo
 import pytest
 from pymongo.errors import OperationFailure
-from pymongo_inmemory import MongoClient
+from pymongo.mongo_client import MongoClient
+from pymongo_inmemory import MongoClient as InMemoryMongoClient
 
 from cachier import cachier
 from cachier.base_core import RecalculationNeeded
 from cachier.mongo_core import _MongoCore
 
+
+# === Enables testing vs a real MongoDB instance ===
+CFG = Birch("cachier")
+
+
+class CfgKey():
+    HOST = "TEST_HOST"
+    UNAME = "TEST_USERNAME"
+    PWD = "TEST_PASSWORD"
+    DB = "TEST_DB"
+    TEST_VS_LIVE_MONGO = "TEST_VS_LIVE_MONGO"
+
+
+URI_TEMPLATE = (
+    "mongodb+srv://{uname}:{pwd}@{host}/{db}?retrywrites=true&w=majority")
+
+
+def _get_cachier_db_mongo_client():
+    host = quote_plus(CFG[CfgKey.HOST])
+    uname = quote_plus(CFG[CfgKey.UNAME])
+    pwd = quote_plus(CFG[CfgKey.PWD])
+    db = quote_plus(CFG[CfgKey.DB])
+    uri = URI_TEMPLATE.format(host=host, uname=uname, pwd=pwd, db=db)
+    client = MongoClient(uri)
+    return client
+
+
 _COLLECTION_NAME = 'cachier_test_{}_{}.{}.{}'.format(
     platform.system(), sys.version_info[0], sys.version_info[1],
     sys.version_info[2])
 
 
 def _test_mongetter():
     if not hasattr(_test_mongetter, 'client'):
-        _test_mongetter.client = MongoClient()
+        if CFG.mget(CfgKey.TEST_VS_LIVE_MONGO, bool):
+            print("Using live MongoDB instance for testing.")
+            _test_mongetter.client = _get_cachier_db_mongo_client()
+        else:
+            print("Using in-memory MongoDB instance for testing.")
+            _test_mongetter.client = InMemoryMongoClient()
     db_obj = _test_mongetter.client['cachier_test']
     if _COLLECTION_NAME not in db_obj.list_collection_names():
         db_obj.create_collection(_COLLECTION_NAME)