diff --git a/configuration/lambda_config.json b/configuration/lambda_config.json
index 32060970..98fcd2ca 100755
--- a/configuration/lambda_config.json
+++ b/configuration/lambda_config.json
@@ -11,9 +11,9 @@
       "us-east-1"
     ]
   },
-  "config_cache_ttl": 2,
+  "config_cache_ttl": $EXODUS_CONFIG_CACHE_TTL,
   "headers": {
-    "max_age": "600"
+    "max_age": "$EXODUS_HEADERS_MAX_AGE"
   },
   "logging": {
     "version": 1,
@@ -27,10 +27,10 @@
     },
     "loggers": {
       "origin-response": {
-        "level": "WARNING"
+        "level": "$ORIGIN_RESPONSE_LOGGER_LEVEL"
       },
       "origin-request": {
-        "level": "WARNING"
+        "level": "$ORIGIN_REQUEST_LOGGER_LEVEL"
       },
       "default": {
         "level": "WARNING"
diff --git a/exodus_lambda/functions/base.py b/exodus_lambda/functions/base.py
index 9c06f240..3903e4d5 100644
--- a/exodus_lambda/functions/base.py
+++ b/exodus_lambda/functions/base.py
@@ -18,22 +18,8 @@ def conf(self):
             if isinstance(self._conf_file, dict):
                 self._conf = self._conf_file
             else:
-                for conf_file in [
-                    self._conf_file,
-                    os.path.join(
-                        os.path.dirname(
-                            os.path.dirname(os.path.dirname(__file__))
-                        ),
-                        "configuration",
-                        "lambda_config.json",
-                    ),
-                ]:
-                    if os.path.exists(conf_file):
-                        with open(
-                            conf_file, "r", encoding="UTF-8"
-                        ) as json_file:
-                            self._conf = json.load(json_file)
-                        break
+                with open(self._conf_file, "r", encoding="UTF-8") as json_file:
+                    self._conf = json.load(json_file)
         return self._conf
 
     @property
diff --git a/exodus_lambda/functions/origin_request.py b/exodus_lambda/functions/origin_request.py
index 47411b5c..b8aacc06 100755
--- a/exodus_lambda/functions/origin_request.py
+++ b/exodus_lambda/functions/origin_request.py
@@ -1,4 +1,5 @@
 import json
+import os
 import time
 import urllib
 from datetime import datetime, timedelta, timezone
@@ -8,9 +9,11 @@
 
 from .base import LambdaBase
 
+CONF_FILE = os.environ.get("EXODUS_LAMBDA_CONF_FILE") or "lambda_config.json"
+
 
 class OriginRequest(LambdaBase):
-    def __init__(self, conf_file="lambda_config.json"):
+    def __init__(self, conf_file=CONF_FILE):
         super().__init__("origin-request", conf_file)
         self._db_client = None
         self._cache = cachetools.TTLCache(
diff --git a/exodus_lambda/functions/origin_response.py b/exodus_lambda/functions/origin_response.py
index 6ec3c4da..64c703c5 100755
--- a/exodus_lambda/functions/origin_response.py
+++ b/exodus_lambda/functions/origin_response.py
@@ -1,11 +1,14 @@
 import json
+import os
 from base64 import b64encode
 
 from .base import LambdaBase
 
+CONF_FILE = os.environ.get("EXODUS_LAMBDA_CONF_FILE") or "lambda_config.json"
+
 
 class OriginResponse(LambdaBase):
-    def __init__(self, conf_file="lambda_config.json"):
+    def __init__(self, conf_file=CONF_FILE):
         super().__init__("origin-response", conf_file)
 
     def handler(self, event, context):
diff --git a/scripts/build-package b/scripts/build-package
index 01ebfa53..2fffabcc 100755
--- a/scripts/build-package
+++ b/scripts/build-package
@@ -1,6 +1,11 @@
 #!/bin/bash
 set -e
 
+export ORIGIN_RESPONSE_LOGGER_LEVEL=${ORIGIN_RESPONSE_LOGGER_LEVEL:-WARNING}
+export ORIGIN_REQUEST_LOGGER_LEVEL=${ORIGIN_REQUEST_LOGGER_LEVEL:-WARNING}
+export EXODUS_HEADERS_MAX_AGE=${EXODUS_HEADERS_MAX_AGE:-600}
+export EXODUS_CONFIG_CACHE_TTL=${EXODUS_CONFIG_CACHE_TTL:-2}
+
 pip install --require-hashes -r requirements.txt --target ./package
 pip install --no-deps --target ./package .
 cp ./configuration/exodus-lambda-deploy.yaml ./package
diff --git a/tests/conftest.py b/tests/conftest.py
index 7d1bb2e5..b0dd7dfa 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,7 @@
+import os
+import subprocess
+import tempfile
+
 import boto3
 import pytest
 
@@ -41,3 +45,40 @@ def cdn_test_url(request):
     else:
         pytest.skip("Test skipped without --cdn-test-url or --lambda-stack")
     return url
+
+
+def mock_conf_file():
+    temp_file = tempfile.NamedTemporaryFile(prefix="lambda_unittests_")
+
+    os.environ["EXODUS_LAMBDA_CONF_FILE"] = temp_file.name
+
+    test_env = os.environ.copy()
+
+    test_env["PROJECT"] = "test"
+    test_env["ENV_TYPE"] = "dev"
+    test_env["EXODUS_CONFIG_CACHE_TTL"] = "2"
+    test_env["ORIGIN_RESPONSE_LOGGER_LEVEL"] = "DEBUG"
+    test_env["ORIGIN_REQUEST_LOGGER_LEVEL"] = "DEBUG"
+    test_env["EXODUS_HEADERS_MAX_AGE"] = "600"
+
+    cmd = "envsubst < ./configuration/lambda_config.json > {temp_path}"
+    cmd = cmd.format(temp_path=temp_file.name)
+
+    subprocess.run(
+        cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+        check=True,
+        shell=True,
+        env=test_env,
+    )
+
+    return temp_file
+
+
+MOCK_LAMBDA_CONF_FILE = mock_conf_file()
+
+
+def pytest_sessionfinish(session, exitstatus):
+    # remove temp conf after whole test run finished
+    MOCK_LAMBDA_CONF_FILE.close()
diff --git a/tests/functions/test_alias.py b/tests/functions/test_alias.py
index d7b73d4f..d377e869 100644
--- a/tests/functions/test_alias.py
+++ b/tests/functions/test_alias.py
@@ -5,8 +5,7 @@
 
 from ..test_utils.utils import generate_test_config
 
-CONF_PATH = "configuration/lambda_config.json"
-TEST_CONF = generate_test_config(CONF_PATH)
+TEST_CONF = generate_test_config()
 
 Alias = namedtuple("Alias", ["src", "dest"])
 
diff --git a/tests/functions/test_base.py b/tests/functions/test_base.py
index 250d7be3..648ffc19 100644
--- a/tests/functions/test_base.py
+++ b/tests/functions/test_base.py
@@ -1,4 +1,5 @@
 import logging
+import os
 
 import pytest
 
@@ -6,13 +7,13 @@
 
 from ..test_utils.utils import generate_test_config
 
-CONF_PATH = "configuration/lambda_config.json"
-TEST_CONF = generate_test_config(CONF_PATH)
+CONF_FILE = os.environ.get("EXODUS_LAMBDA_CONF_FILE")
+TEST_CONF = generate_test_config()
 
 
 def test_base_handler():
     with pytest.raises(NotImplementedError):
-        LambdaBase(conf_file=CONF_PATH).handler(event=None, context=None)
+        LambdaBase(conf_file=CONF_FILE).handler(event=None, context=None)
 
 
 @pytest.mark.parametrize(
diff --git a/tests/functions/test_origin_request.py b/tests/functions/test_origin_request.py
index 3c4e865d..de983299 100644
--- a/tests/functions/test_origin_request.py
+++ b/tests/functions/test_origin_request.py
@@ -11,8 +11,7 @@
 
 TEST_PATH = "/origin/rpms/repo/ver/dir/filename.ext"
 MOCKED_DT = "2020-02-17T15:38:05.864+00:00"
-CONF_PATH = "configuration/lambda_config.json"
-TEST_CONF = generate_test_config(CONF_PATH)
+TEST_CONF = generate_test_config()
 
 
 @pytest.mark.parametrize(
diff --git a/tests/functions/test_origin_response.py b/tests/functions/test_origin_response.py
index fe7841cf..0c3447af 100644
--- a/tests/functions/test_origin_response.py
+++ b/tests/functions/test_origin_response.py
@@ -6,8 +6,7 @@
 
 from ..test_utils.utils import generate_test_config
 
-CONF_PATH = "configuration/lambda_config.json"
-TEST_CONF = generate_test_config(CONF_PATH)
+TEST_CONF = generate_test_config()
 MAX_AGE = TEST_CONF["headers"]["max_age"]
 
 
@@ -60,7 +59,7 @@ def test_origin_response_valid_headers(original_uri, want_digest):
             }
         ]
 
-    response = OriginResponse(conf_file=CONF_PATH).handler(event, context=None)
+    response = OriginResponse(conf_file=TEST_CONF).handler(event, context=None)
     assert response["headers"] == expected_headers
 
 
@@ -75,14 +74,14 @@ def test_origin_response_empty_headers(test_input):
         ]
     }
 
-    response = OriginResponse(conf_file=CONF_PATH).handler(event, context=None)
+    response = OriginResponse(conf_file=TEST_CONF).handler(event, context=None)
     assert response["headers"] == {}
 
 
 def test_origin_response_missing_headers():
     event = {"Records": [{"cf": {"request": {}, "response": {}}}]}
 
-    response = OriginResponse(conf_file=CONF_PATH).handler(event, context=None)
+    response = OriginResponse(conf_file=TEST_CONF).handler(event, context=None)
     assert response == {}
 
 
diff --git a/tests/test_utils/utils.py b/tests/test_utils/utils.py
index c275a63e..2f74ae8b 100644
--- a/tests/test_utils/utils.py
+++ b/tests/test_utils/utils.py
@@ -1,8 +1,10 @@
 import json
 import os
 
+CONF_FILE = os.environ.get("EXODUS_LAMBDA_CONF_FILE")
 
-def generate_test_config(conf="configuration/lambda_config.json"):
+
+def generate_test_config(conf=CONF_FILE):
     with open(conf, "r") as json_file:
         conf = json.load(json_file)