The testing discipline that prevents regulatory failure, data corruption, and sleepless nights in Financial Services. Slowly Changing Dimension Type 2 pipelines underpin regulatory reporting, remediation, risk models, and point-in-time evidence across Financial Services — yet most are effectively untested. As data platforms adopt CDC, hybrid SCD2 patterns, and large-scale reprocessing, silent temporal defects become both more likely and harder to detect. This article sets out a production-grade testing discipline for SCD2 and temporal pipelines, focused on determinism, late data, precedence, replay, and PIT reconstruction. The goal is simple: prevent silent corruption and ensure SCD2 outputs remain defensible under regulatory scrutiny.