How do i mock an attribute within nested constructor using unittest - python-3.x

Question

This is what i am trying to test :
src/DBOps.py
class DBOps() :
class dynamodbOps() :
def __init__(self,db_table) :
dynamodb = boto3.resource('dynamodb')
self.table = dynamodb.Table(db_table)
def GetDBItem(self,pool):
response = self.table.get_item(Key={'pool' : pool})
And this is the test case that is unsuccessful :
class test_GetDBItem(unittest.TestCase) :
def setUp(self):
self.db_ops = DBOps()
db_table = "test_table"
self.dyn = self.db_ops.dynamodbOps(db_table)
#mock.patch('src.DBOps')
def test_run_query_with_item(self, getItem_mock) :
getItem_mock.dynamodbOps.table.get_item.return_value = {"Blah":"Blah Blah"}
pool = 'some_pool'
response = self.dyn.GetDBItem(pool)
I am trying to mock the 'table.get_item' call and failing at it no matter what i try. Any pointers would be great!

Answer 1

Figured it out as below :
class test_GetDBItem(unittest.TestCase) :
def setUp(self):
db_ops = DBOps()
db_table = "test_table"
self.dyn = db_ops.dynamodbOps(db_table)
def test_run_query_with_item(self) :
with patch.object(self.dyn.table, 'get_item') as getItem_mock :
getItem_mock.return_value = {"Blah":"Blah Blah"}
pool = 'some pool'
response = self.dyn.GetDBItem(quadra_pool)