diff --git a/Makefile b/Makefile
index f8093725b..ced5646be 100644
--- a/Makefile
+++ b/Makefile
@@ -21,6 +21,7 @@ CONTAINER ?= false
 VENV_PATH_PREFIX := $(if $(filter true,$(CONTAINER)),./.venv,./lambdas/venv)
 FORMAT_ALL ?= false
 CHECK ?= false
+ARGS ?= ""
 
 .PHONY: \
 	install clean help format list requirements ruff build-and-deploy-sandbox \
@@ -169,10 +170,10 @@ endif
 test-unit:
 ifeq ($(CONTAINER), true)
 	cd ./lambdas && \
-	PYTHONPATH=. poetry run pytest tests/unit ../scripts/github/checklist_validator/tests
+	PYTHONPATH=. poetry run pytest $(if $(ARGS),$(ARGS),tests/unit ../scripts/github/checklist_validator/tests)
 else
 	cd ./lambdas && \
-	PYTHONPATH=.. ./venv/bin/python3 -m pytest tests/unit ../scripts/github/checklist_validator/tests
+	PYTHONPATH=.. ./venv/bin/python3 -m pytest $(if $(ARGS),$(ARGS),tests/unit ../scripts/github/checklist_validator/tests)
 endif
 
 test-unit-coverage:
diff --git a/lambdas/tests/unit/handlers/test_pdm_post_fhir_document_reference_handler.py b/lambdas/tests/unit/handlers/test_pdm_post_fhir_document_reference_handler.py
index 6d07a8c58..7352146ff 100644
--- a/lambdas/tests/unit/handlers/test_pdm_post_fhir_document_reference_handler.py
+++ b/lambdas/tests/unit/handlers/test_pdm_post_fhir_document_reference_handler.py
@@ -1,9 +1,12 @@
 import json
+from unittest.mock import patch
 
 import pytest
 
+from enums.lambda_error import LambdaError
 from handlers.post_fhir_document_reference_handler import lambda_handler
 from tests.unit.conftest import APIM_API_URL
+from utils.lambda_exceptions import DocumentRefException
 
 
 @pytest.fixture
@@ -83,3 +86,51 @@ def test_mtls_lambda_handler_success(valid_mtls_event, context, mock_service):
         valid_mtls_event["body"],
         valid_mtls_event["requestContext"],
     )
+
+
+def test_lambda_handler_missing_body(context):
+    event = {"requestContext": {}}
+
+    response = lambda_handler(event, context)
+
+    assert response["statusCode"] >= 400  # Lambda error
+    assert "resourceType" in json.loads(response["body"])  # FHIR error structure
+
+
+@patch("handlers.post_fhir_document_reference_handler.PostFhirDocumentReferenceService")
+def test_lambda_handler_document_ref_exception(mock_service, event, context):
+    mock_instance = mock_service.return_value
+
+    mock_exception = DocumentRefException(
+        status_code=400,
+        error=LambdaError.DocRefNoParse,
+        details="Invalid doc reference",
+    )
+
+    # Raises exception when processing
+    mock_instance.process_fhir_document_reference.side_effect = mock_exception
+
+    response = lambda_handler(event, context)
+
+    assert response["statusCode"] == 400
+    # Ensure body contains structured FHIR error
+    body = json.loads(response["body"])
+    assert "resourceType" in body
+    assert body["resourceType"] == "OperationOutcome"
+
+
+@patch("handlers.post_fhir_document_reference_handler.PostFhirDocumentReferenceService")
+def test_lambda_handler_location_header_format(mock_service, event, context):
+    mock_instance = mock_service.return_value
+    mock_instance.process_fhir_document_reference.return_value = (
+        {"id": "XYZ-987"},
+        "XYZ-987",
+    )
+
+    response = lambda_handler(event, context)
+    print(response)
+
+    assert (
+        response["headers"]["Location"] == f"{APIM_API_URL}/DocumentReference/XYZ-987"
+    )
+    assert response["statusCode"] == 201