Rule 206(4)‑7 under the Investment Advisers Act of 1940, commonly known as the “Compliance Rule,” requires advisers to review the adequacy and effectiveness of their compliance policies and procedures. One of the essential tools advisers use to fulfill their obligations under the Compliance Rule is testing. An ACA Group presentation, part of its “Building a Gold Standard Compliance Program” series, examined the role of testing in a compliance program; hallmarks of effective testing; and testing design and implementation. The program featured L. Allison Charley, director, and Jaqueline Hummel, director of thought leadership, at ACA Group. This article synthesizes their insights. For coverage of prior installments in that series, see “Managing Conflicts and Developing Effective Compliance Policies and Procedures” (Jan. 4, 2024); and “Improving Compliance Programs With Gap Analysis and Risk Assessments” (Oct. 26, 2023).