Fix auto sync trigger logic and add tests

test/controllers/concerns/auto_sync_test.rb

@@ -0,0 +1,41 @@
+require "test_helper"
+
+class AutoSyncTest < ActionDispatch::IntegrationTest
+  setup do
+    sign_in @user = users(:family_admin)
+    @family = @user.family
+
+    # Start fresh
+    Sync.destroy_all
+  end
+
+  test "auto-syncs family if hasn't synced" do
+    assert_difference "Sync.count", 1 do
+      get root_path
+    end
+  end
+
+  test "auto-syncs family if hasn't synced in last 24 hours" do
+    # If request comes in at beginning of day, but last sync was 1 hour ago ("yesterday"), we still sync
+    travel_to Time.current.beginning_of_day
+    last_sync_datetime = 1.hour.ago
+
+    Sync.create!(syncable: @family, created_at: last_sync_datetime)
+
+    assert_difference "Sync.count", 1 do
+      get root_path
+    end
+  end
+
+  test "does not auto-sync if family has synced today already" do
+    travel_to Time.current.end_of_day
+
+    last_created_sync_at = 23.hours.ago
+
+    Sync.create!(syncable: @family, created_at: last_created_sync_at)
+
+    assert_no_difference "Sync.count" do
+      get root_path
+    end
+  end
+end