modules/spring-mock-mvc/src/main/java/io/restassured/module/mockmvc/internal/MockMvcRequestSpecificationImpl.java
public MockMvcRequestSpecification sessionAttr(String name, Object value) {
        notNull(name, "Session attribute name");
        parameterUpdater.updateZeroToManyParameters(convert(cfg.getMockMvcParamConfig().sessionAttributesUpdateStrategy()), sessionAttributes, name, value);
        return this;
    }
public MockMvcRequestSpecification sessionAttr(String name, Object value) {
        notNull(name, "Session attribute name");
        parameterUpdater.updateZeroToManyParameters(convert(cfg.getMockMvcParamConfig().sessionAttributesUpdateStrategy()), sessionAttributes, name, value);
        return this;
    }
Set a session attribute.

@param name  the session attribute name
@param value the session attribute value