diff --git a/Sources/DatabaseClient/Internal/Rooms.swift b/Sources/DatabaseClient/Internal/Rooms.swift
index ef8470e..f673ddb 100644
--- a/Sources/DatabaseClient/Internal/Rooms.swift
+++ b/Sources/DatabaseClient/Internal/Rooms.swift
@@ -27,6 +27,9 @@ extension DatabaseClient.Rooms: TestDependencyKey {
         model.rectangularSizes?.removeAll {
           $0.id == rectangularDuctID
         }
+        if model.rectangularSizes?.count == 0 {
+          model.rectangularSizes = nil
+        }
         if model.hasChanges {
           try await model.save(on: database)
         }
diff --git a/Tests/DatabaseClientTests/RoomTests.swift b/Tests/DatabaseClientTests/RoomTests.swift
new file mode 100644
index 0000000..70446b1
--- /dev/null
+++ b/Tests/DatabaseClientTests/RoomTests.swift
@@ -0,0 +1,66 @@
+import DatabaseClient
+import Dependencies
+import Foundation
+import ManualDCore
+import Testing
+
+@Suite
+struct RoomTests {
+
+  @Test
+  func happyPath() async throws {
+    try await withTestUserAndProject { _, project in
+      @Dependency(\.database.rooms) var rooms
+
+      let room = try await rooms.create(
+        .init(projectID: project.id, name: "Test", heatingLoad: 1234, coolingTotal: 1234)
+      )
+
+      let fetched = try await rooms.fetch(project.id)
+      #expect(fetched == [room])
+
+      let got = try await rooms.get(room.id)
+      #expect(got == room)
+
+      let updated = try await rooms.update(
+        room.id,
+        .init(rectangularSizes: [.init(id: UUID(0), register: 1, height: 8)])
+      )
+      #expect(updated.id == room.id)
+
+      let updatedSize = try await rooms.updateRectangularSize(
+        room.id, .init(id: UUID(0), register: 1, height: 10)
+      )
+      #expect(updatedSize.id == room.id)
+
+      let deletedSize = try await rooms.deleteRectangularSize(room.id, UUID(0))
+      #expect(deletedSize.rectangularSizes == nil)
+
+      try await rooms.delete(room.id)
+
+    }
+  }
+
+  @Test
+  func notFound() async throws {
+    try await withDatabase {
+      @Dependency(\.database.rooms) var rooms
+
+      await #expect(throws: NotFoundError.self) {
+        try await rooms.delete(UUID(0))
+      }
+
+      await #expect(throws: NotFoundError.self) {
+        try await rooms.deleteRectangularSize(UUID(0), UUID(1))
+      }
+
+      await #expect(throws: NotFoundError.self) {
+        try await rooms.update(UUID(0), .init())
+      }
+
+      await #expect(throws: NotFoundError.self) {
+        try await rooms.updateRectangularSize(UUID(0), .init(height: 8))
+      }
+    }
+  }
+}