EasyMock is a Java-based testing framework that allows developers to create mock objects for unit testing. It helps simulate the behavior of complex components, enabling developers to test individual parts of their code in isolation. This is particularly useful when the actual components are unavailable or difficult to use during testing. With EasyMock, developers can define expectations for method calls on mock objects, including return values and argument matching. This makes it easier to verify that the code interacts correctly with its dependencies, leading to more reliable and maintainable software. Overall, EasyMock simplifies the testing process and enhances code quality.