Define default request properties that should be merged into all
performed requests. In effect this provides a mechanism for defining
common initialization for all requests such as the content type, request
parameters, session attributes, and any other request property.
Properties specified at the time of performing a request override the
default properties defined here.
Add a MockMvcConfigurer that automates MockMvc setup and
configures it for some specific purpose (e.g. security).
There is a built-in SharedHttpSessionConfigurer that can be
used to re-use the HTTP session across requests. 3rd party frameworks
like Spring Security also use this mechanism to provide configuration