diff --git a/api/tests/test_user_sign_in.py b/api/tests/test_user_sign_in.py
new file mode 100644
index 0000000000..80d1adb161
--- /dev/null
+++ b/api/tests/test_user_sign_in.py
@@ -0,0 +1,92 @@
+import sys
+import os
+from os.path import dirname, join, expanduser, normpath, realpath
+
+import pyotp
+import pytest
+from flask_bcrypt import Bcrypt
+from graphene.test import Client
+
+
+# This is the only way I could get imports to work for unit testing.
+PACKAGE_PARENT = '..'
+SCRIPT_DIR = dirname(realpath(join(os.getcwd(), expanduser(__file__))))
+sys.path.append(normpath(join(SCRIPT_DIR, PACKAGE_PARENT)))
+
+from manage import seed, remove_seed
+seed()
+from db import *
+from app import app
+from queries import schema
+from models import Users
+from functions.error_messages import(
+    error_invalid_credentials
+)
+remove_seed()
+
+
+@pytest.fixture(scope='class')
+def user_schema_test_db_init():
+    db.init_app(app)
+    bcrypt = Bcrypt(app)
+
+    with app.app_context():
+        test_user = Users(
+            display_name="testuser",
+            user_name="testuser@testemail.ca",
+            user_password=bcrypt.generate_password_hash(
+                password="testpassword123").decode("UTF-8"),
+        )
+        db.session.add(test_user)
+        db.session.commit()
+
+    yield
+
+    with app.app_context():
+        Users.query.delete()
+        db.session.commit()
+
+
+##
+# This class of tests works within the 'createUser' api endpoint
+@pytest.mark.usefixtures('user_schema_test_db_init')
+class TestSignInUser:
+    def test_successful_sign_in(self):
+        """Test that ensures a user can be signed in"""
+        with app.app_context():
+            client = Client(schema)
+            executed = client.execute(
+                '''
+                mutation{
+                    signIn(userName:"testuser@testemail.ca", password:"testpassword123"){
+                        user{
+                            userName
+                        }
+                    }
+                }
+                ''')
+            assert executed['data']
+            assert executed['data']['signIn']
+            assert executed['data']['signIn']['user']
+            assert executed['data']['signIn']['user']['userName'] == "testuser@testemail.ca"
+
+    def test_invalid_credentials(self):
+        """Test that ensures a user can be signed in"""
+        with app.app_context():
+            client = Client(schema)
+            executed = client.execute(
+                '''
+                mutation{
+                    signIn(userName:"testuser@testemail.ca", password:"testpassword1234"){
+                        user{
+                            userName
+                        }
+                    }
+                }
+                ''')
+            assert executed['errors']
+            assert executed['errors'][0]
+            assert executed['errors'][0]['message']
+            assert executed['errors'][0]['message'] == error_invalid_credentials()
+
+