diff --git a/tests/unit_tests/fixtures/core/config/area_id_collision.yaml b/tests/unit_tests/fixtures/core/config/area_id_collision.yaml
new file mode 100644
index 0000000000..985db073da
--- /dev/null
+++ b/tests/unit_tests/fixtures/core/config/area_id_collision.yaml
@@ -0,0 +1,10 @@
+esphome:
+  name: test-collision
+  area:
+    id: duplicate_id
+    name: Area 1
+  areas:
+    - id: duplicate_id
+      name: Area 2
+
+host:
\ No newline at end of file
diff --git a/tests/unit_tests/fixtures/core/config/device_without_area.yaml b/tests/unit_tests/fixtures/core/config/device_without_area.yaml
new file mode 100644
index 0000000000..cc81953d42
--- /dev/null
+++ b/tests/unit_tests/fixtures/core/config/device_without_area.yaml
@@ -0,0 +1,7 @@
+esphome:
+  name: test-device-no-area
+  devices:
+    - id: test_device
+      name: Test Device
+
+host:
\ No newline at end of file
diff --git a/tests/unit_tests/fixtures/core/config/legacy_string_area.yaml b/tests/unit_tests/fixtures/core/config/legacy_string_area.yaml
new file mode 100644
index 0000000000..136c2aafac
--- /dev/null
+++ b/tests/unit_tests/fixtures/core/config/legacy_string_area.yaml
@@ -0,0 +1,5 @@
+esphome:
+  name: test-legacy-area
+  area: Living Room
+
+host:
\ No newline at end of file
diff --git a/tests/unit_tests/fixtures/core/config/multiple_areas_devices.yaml b/tests/unit_tests/fixtures/core/config/multiple_areas_devices.yaml
new file mode 100644
index 0000000000..0ffee3177c
--- /dev/null
+++ b/tests/unit_tests/fixtures/core/config/multiple_areas_devices.yaml
@@ -0,0 +1,22 @@
+esphome:
+  name: test-multiple
+  area:
+    id: main_area
+    name: Main Area
+  areas:
+    - id: area1
+      name: Area 1
+    - id: area2
+      name: Area 2
+  devices:
+    - id: device1
+      name: Device 1
+      area_id: main_area
+    - id: device2
+      name: Device 2
+      area_id: area1
+    - id: device3
+      name: Device 3
+      area_id: area2
+
+host:
\ No newline at end of file
diff --git a/tests/unit_tests/fixtures/core/config/valid_area_device.yaml b/tests/unit_tests/fixtures/core/config/valid_area_device.yaml
new file mode 100644
index 0000000000..54e1262819
--- /dev/null
+++ b/tests/unit_tests/fixtures/core/config/valid_area_device.yaml
@@ -0,0 +1,11 @@
+esphome:
+  name: test-valid-area
+  areas:
+    - id: bedroom_area
+      name: Bedroom
+  devices:
+    - id: test_device
+      name: Test Device
+      area_id: bedroom_area
+
+host:
\ No newline at end of file