diff --git a/apiserver/tests/factories/models/code.py b/apiserver/tests/factories/models/code.py
index 74da50796..465a81624 100644
--- a/apiserver/tests/factories/models/code.py
+++ b/apiserver/tests/factories/models/code.py
@@ -80,6 +80,7 @@ def get_pull_request_event(
     created_at=None,
     idempotency_key=None,
     org_repo_id=None,
+    data=None,
 ):
     return PullRequestEvent(
         id=id or uuid4(),
@@ -89,7 +90,9 @@ def get_pull_request_event(
             "user": {"login": reviewer or "User"},
             "state": state or "APPROVED",
             "author_association": "NONE",
-        },
+        }
+        if not data
+        else data,
         created_at=created_at or time_now(),
         idempotency_key=idempotency_key or str(randint(10, 100)),
         org_repo_id=org_repo_id or uuid4(),
diff --git a/apiserver/tests/factories/models/exapi/github.py b/apiserver/tests/factories/models/exapi/github.py
index d1fa08e03..0c3c71879 100644
--- a/apiserver/tests/factories/models/exapi/github.py
+++ b/apiserver/tests/factories/models/exapi/github.py
@@ -1,10 +1,17 @@
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Dict
+
+from dora.utils.time import time_now
+
+
 def get_github_commit_dict(
     sha: str = "123456789098765",
     author_login: str = "author_abc",
     url: str = "https://github.com/123456789098765",
     message: str = "[abc 315] avoid mapping edit state",
     created_at: str = "2022-06-29T10:53:15Z",
-):
+) -> Dict:
     return {
         "sha": sha,
         "commit": {
@@ -19,3 +26,29 @@ def get_github_commit_dict(
         },
         "html_url": url,
     }
+
+
+@dataclass
+class GithubPullRequestReview:
+    id: str
+    submitted_at: datetime
+    user_login: str
+
+    @property
+    def raw_data(self):
+        return {
+            "id": self.id,
+            "submitted_at": self.submitted_at,
+            "user": {
+                "login": self.user_login,
+            },
+        }
+
+
+def get_github_pull_request_review(
+    review_id: str = "123456",
+    submitted_at: datetime = time_now(),
+    user_login: str = "abc",
+) -> GithubPullRequestReview:
+
+    return GithubPullRequestReview(review_id, submitted_at, user_login)
diff --git a/apiserver/tests/service/code/sync/test_etl_github_handler.py b/apiserver/tests/service/code/sync/test_etl_github_handler.py
index 38fe62144..fb11c7180 100644
--- a/apiserver/tests/service/code/sync/test_etl_github_handler.py
+++ b/apiserver/tests/service/code/sync/test_etl_github_handler.py
@@ -4,13 +4,93 @@
 
 from dora.service.code.sync.etl_github_handler import GithubETLHandler
 from dora.utils.string import uuid4_str
-from tests.factories.models import get_pull_request, get_pull_request_commit
-from tests.factories.models.exapi.github import get_github_commit_dict
+from tests.factories.models import (
+    get_pull_request,
+    get_pull_request_commit,
+    get_pull_request_event,
+)
+from tests.factories.models.exapi.github import (
+    get_github_commit_dict,
+    get_github_pull_request_review,
+)
 from tests.utilities import compare_objects_as_dicts
 
 ORG_ID = uuid4_str()
 
 
+def test__to_pr_events_given_an_empty_list_of_events_returns_an_empty_list():
+    pr_model = get_pull_request()
+    assert GithubETLHandler._to_pr_events([], pr_model, []) == []
+
+
+def test__to_pr_events_given_a_list_of_only_new_events_returns_a_list_of_pr_events():
+    pr_model = get_pull_request()
+    event1 = get_github_pull_request_review()
+    event2 = get_github_pull_request_review()
+    events = [event1, event2]
+
+    pr_events = GithubETLHandler._to_pr_events(events, pr_model, [])
+
+    expected_pr_events = [
+        get_pull_request_event(
+            pull_request_id=str(pr_model.id),
+            org_repo_id=pr_model.repo_id,
+            data=event1.raw_data,
+            created_at=event1.submitted_at,
+            type="REVIEW",
+            idempotency_key=event1.id,
+            reviewer=event1.user_login,
+        ),
+        get_pull_request_event(
+            pull_request_id=str(pr_model.id),
+            org_repo_id=pr_model.repo_id,
+            data=event2.raw_data,
+            created_at=event2.submitted_at,
+            type="REVIEW",
+            idempotency_key=event2.id,
+            reviewer=event2.user_login,
+        ),
+    ]
+
+    for event, expected_event in zip(pr_events, expected_pr_events):
+        assert compare_objects_as_dicts(event, expected_event, ["id"]) is True
+
+
+def test__to_pr_events_given_a_list_of_new_events_and_old_events_returns_a_list_of_pr_events():
+    pr_model = get_pull_request()
+    event1 = get_github_pull_request_review()
+    event2 = get_github_pull_request_review()
+    events = [event1, event2]
+
+    old_event = get_pull_request_event(
+        pull_request_id=str(pr_model.id),
+        org_repo_id=pr_model.repo_id,
+        data=event1.raw_data,
+        created_at=event1.submitted_at,
+        type="REVIEW",
+        idempotency_key=event1.id,
+        reviewer=event1.user_login,
+    )
+
+    pr_events = GithubETLHandler._to_pr_events(events, pr_model, [old_event])
+
+    expected_pr_events = [
+        old_event,
+        get_pull_request_event(
+            pull_request_id=str(pr_model.id),
+            org_repo_id=pr_model.repo_id,
+            data=event2.raw_data,
+            created_at=event2.submitted_at,
+            type="REVIEW",
+            idempotency_key=event2.id,
+            reviewer=event2.user_login,
+        ),
+    ]
+
+    for event, expected_event in zip(pr_events, expected_pr_events):
+        assert compare_objects_as_dicts(event, expected_event, ["id"]) is True
+
+
 def test__to_pr_commits_given_an_empty_list_of_commits_returns_an_empty_list():
     pr_model = get_pull_request()
     github_etl_handler = GithubETLHandler(ORG_ID, None, None, None, None)