This article reports on an intervention study conducted to improve young Thai learners' motivation and attitudes towards take-home tests. The traditional use of summative tests in education has often led to increased pressure and demotivation among students. Based on formative assessment practices and motivational strategies, the study aimed to improve students' motivation and engagement when taking tests. The intervention involved regular, short take-home tests and motivational strategies over 25 weeks and collected data using a mixed methods approach. Results showed notable improvement in students' intrinsic motivation, writing motivation and homework completion rate of take-home tests over the course of the intervention. The article highlights the importance of incorporating formative assessment practices, goal setting, collaborative learning and visual aids to promote student ownership of learning and increase their motivation to complete tests. The study contributes to the ongoing dialogue on effective assessment methods and student motivation in an educational context.