Add a tox github action and fix the test

.github/workflows/tox.yaml

@@ -0,0 +1,18 @@
+name: Tests
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+      - name: Install Tox and any other packages
+        run: pip install tox
+      - name: Run Tox
+        # Run tox using the version of Python in `PATH`
+        run: tox -e py

cost-reporter/src/lambda_function.py

@@ -55,6 +55,8 @@ def get_daily_cost(days):
 
 
 def trigger_notification(graph_data):
+    """ Determines whether or not to send the notification
+    """
     should_send = True
 
     total_cost_today = 0
@@ -66,7 +68,7 @@ def trigger_notification(graph_data):
     logging.info(f"Total cost yesterday: {total_cost_yesterday}")
 
     only_notify_on_increase = os.environ["ONLY_NOTIFY_ON_INCREASE"]
-    if only_notify_on_increase == "true":
+    if only_notify_on_increase.lower() == "true":
         if total_cost_today < total_cost_yesterday:
             logging.info("Not sending, since cost did not increase and I should only notify on increase.")
             should_send = False

tox.ini

@@ -0,0 +1,10 @@
+[tox]
+envlist = py38
+# allows us to run tox without setup.py
+skipsdist = True
+
+[testenv]
+deps = -r{toxinidir}/cost-reporter/requirements-dev.txt
+commands = pytest
+setenv =
+    PYTHONPATH={toxinidir}/cost-reporter/src