One of my favorites of Christian Schwarz’s books is The 3 Colors of Love. In this volume of his 3 colors series he looks at how to evaluate your growth in the fruit of the Spirit.
With solid biblical exegesis, he traces the word love throughout scripture to incorporate grace, justice, and truth: represented by the 3 colors blue, green, and red. In a very holistic understanding, the core of the book asserts that there is only one fruit of the Spirit– Love– along with its 8 descriptors: joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control. Schwarz makes an excellent case for this interpretation.
The 3 Colors of Love comes with a survey you can take to measure yourself in the fruit of the Spirit and continue growing toward maturity. It’s a theologically sound and very practical resource. Highly recommended.