diff --git a/app/templates/partials/day_detail.html b/app/templates/partials/day_detail.html
new file mode 100644
index 0000000..679c412
--- /dev/null
+++ b/app/templates/partials/day_detail.html
@@ -0,0 +1,30 @@
+{% set weekday_names = ["월", "화", "수", "목", "금", "토", "일"] %}
+
+
+
{{ log_date.strftime("%Y.%m.%d") }} ({{ weekday_names[log_date.weekday()] }})
+
+
+ {% if items %}
+
+ {% for item in items %}
+
+
+ {{ item.name }}
+ {{ "형성" if item.habit_type == "build" else "중단" }}
+
+ {% if item.status == "checked" %}
+ 완료
+ {% elif item.status == "failed" %}
+ 실패
+ {% elif item.status == "missed" %}
+ 미완료
+ {% else %}
+ 예정
+ {% endif %}
+
+ {% endfor %}
+
+ {% else %}
+
이 날 예정된 습관이 없어요.
+ {% endif %}
+
diff --git a/tests/test_log_service.py b/tests/test_log_service.py
index d04db7c..082d3d4 100644
--- a/tests/test_log_service.py
+++ b/tests/test_log_service.py
@@ -407,6 +407,53 @@ def test_get_monthly_summary_does_not_count_failed_as_checked(db_session, test_u
assert by_date[date(2026, 3, 5)].checked_count == 0
+# ---- get_day_detail ----
+
+
+def test_get_day_detail_marks_checked_and_failed(db_session, test_user):
+ checked_habit = _make_habit(db_session, test_user.id, name="체크됨", created_at=datetime(2026, 3, 1))
+ failed_habit = _make_habit(db_session, test_user.id, name="실패함", created_at=datetime(2026, 3, 1))
+ _check(db_session, checked_habit.id, date(2026, 3, 5))
+ _fail(db_session, failed_habit.id, date(2026, 3, 5))
+
+ items = log_service.get_day_detail(db_session, test_user.id, date(2026, 3, 5))
+ by_name = {i.name: i for i in items}
+ assert by_name["체크됨"].status == "checked"
+ assert by_name["실패함"].status == "failed"
+
+
+def test_get_day_detail_marks_past_unlogged_as_missed(db_session, test_user):
+ habit = _make_habit(db_session, test_user.id, created_at=datetime(2026, 3, 1))
+
+ items = log_service.get_day_detail(db_session, test_user.id, date(2026, 3, 5))
+ assert items[0].status == "missed"
+
+
+def test_get_day_detail_marks_future_unlogged_as_pending(db_session, test_user):
+ habit = _make_habit(db_session, test_user.id)
+ future = date.today() + timedelta(days=1)
+
+ items = log_service.get_day_detail(db_session, test_user.id, future)
+ assert items[0].status == "pending"
+
+
+def test_get_day_detail_excludes_days_before_habit_created(db_session, test_user):
+ _make_habit(db_session, test_user.id, created_at=datetime(2026, 3, 10))
+
+ items = log_service.get_day_detail(db_session, test_user.id, date(2026, 3, 5))
+ assert items == []
+
+
+def test_get_day_detail_excludes_unscheduled_weekdays(db_session, test_user):
+ monday_only_mask = 0b0000001 # bit0 = 월요일
+ _make_habit(db_session, test_user.id, created_at=datetime(2026, 3, 1), weekdays_mask=monday_only_mask)
+
+ tuesday = date(2026, 3, 3)
+ assert tuesday.weekday() == 1
+ items = log_service.get_day_detail(db_session, test_user.id, tuesday)
+ assert items == []
+
+
# ---- summarize_completion_rate: 미래 날짜 제외 회귀 테스트 ----
# CLAUDE.md에 기록된 실제 버그: 미래 날짜를 포함시키면 완료율이 부당하게 낮게 나온다
# (실제로 6.2% -> 수정 후 50%가 된 사례).
diff --git a/tests/test_pages_history.py b/tests/test_pages_history.py
new file mode 100644
index 0000000..2b93c59
--- /dev/null
+++ b/tests/test_pages_history.py
@@ -0,0 +1,41 @@
+from datetime import date, datetime
+
+from app.models.habit import ALL_WEEKDAYS_MASK, HabitType
+from app.schemas.habit import HabitCreate
+from app.services import habit_service
+
+
+def _make_habit(db_session, user_id, name="테스트 습관", created_at=None, **overrides):
+ data = HabitCreate(
+ name=name,
+ habit_type=overrides.pop("habit_type", HabitType.BUILD),
+ weekdays_mask=overrides.pop("weekdays_mask", ALL_WEEKDAYS_MASK),
+ )
+ habit = habit_service.create_habit(db_session, user_id, data)
+ if created_at is not None:
+ habit.created_at = created_at
+ db_session.commit()
+ db_session.refresh(habit)
+ return habit
+
+
+def test_history_day_detail_shows_scheduled_habit(auth_client, db_session, test_user):
+ _make_habit(db_session, test_user.id, name="아침 스트레칭", created_at=datetime(2026, 3, 1))
+
+ response = auth_client.get("/history/day/2026-03-05")
+ assert response.status_code == 200
+ assert "아침 스트레칭" in response.text
+
+
+def test_history_day_detail_excludes_other_users_habits(auth_client, db_session, other_user):
+ _make_habit(db_session, other_user.id, name="남의 습관", created_at=datetime(2026, 3, 1))
+
+ response = auth_client.get("/history/day/2026-03-05")
+ assert response.status_code == 200
+ assert "남의 습관" not in response.text
+
+
+def test_history_day_detail_requires_login(client):
+ response = client.get("/history/day/2026-03-05", follow_redirects=False)
+ assert response.status_code == 303
+ assert response.headers["location"] == "/login"