A test platform provides modular test automation. The modular test automation may include defining modular segments of a test configuration, and testing an Application Under Test (“AUT”) based on the modular segments. The test configuration may define a specific flow or execution ordering for the modular segments. The flow may be changed by reordering the segments, modularly adding new segments anywhere in the flow, removing segments, modifying individual segments without affecting other segments, defining a particular segment once and reusing the particular segment in two or more different test configurations, and/or carrying over a change made to the particular segment in a first test configuration to the particular segment of a second test configuration automatically. The modular test automation may also include modularly selecting a set of nodes for testing the AUT according to the modular segments of the flow.