An overfill prevention mechanism comprising: a conduit (22, 62g) having a conduit wall extending from an inlet end to an outlet end, said conduit wall defining a conduit wall interior surface (32, 72g) and a conduit wall exterior surface, said conduit wall interior surface (32, 72g) defining a fluid path through said conduit (22, 62g) starting at an upstream location at said inlet end and ending at a downstream location at said outlet end; a valve body moveably positioned in said fluid path of said conduit (22, 62g), said valve body actuatable from an open position to a closed position; a valve actuator moveable relative to said valve body between an overfill-prevention position and a filling position, said valve actuator urging said valve body toward said closed position when said valve actuator moves from said filling position to said overfill-prevention position, and said valve actuator permitting said valve body to be in said open position when said valve actuator is in said filling position; and a non-contact test mechanism moveable between a service position and a test position, said non-contact test mechanism comprising: a test actuator coupled to said valve actuator such that actuation of said non-contact test mechanism from said service position to said test position advances said valve actuator from said filling position to said overfill-prevention position, whereby said actuation of said non-contact test mechanism urges said valve body toward said closed position with absence of an overfill condition, and said non-contact test mechanism being positioned outside of said conduit (22, 62g) such that said conduit wall is interposed between said test actuator and said fluid path, said test actuator being operable to advance said valve actuator from said filling position to said overfill-prevention position thereby avoiding physically penetrating said conduit wall, whereby said non-contact test mechanism avoids creation of a leak path in said conduit (22, 62g) in order to function as a test mechanism; characterized in that the non-contact test mechanism is disposed upstream of said valve body. a conduit (22, 62g) having a conduit wall extending from an inlet end to an outlet end, said conduit wall defining a conduit wall interior surface (32, 72g) and a conduit wall exterior surface, said conduit wall interior surface (32, 72g) defining a fluid path through said conduit (22, 62g) starting at an upstream location at said inlet end and ending at a downstream location at said outlet end; a valve body moveably positioned in said fluid path of said conduit (22, 62g), said valve body actuatable from an open position to a closed position; a valve actuator moveable relative to said valve body between an overfill-prevention position and a filling position, said valve actuator urging said valve body toward said closed position when said valve actuator moves from said filling position to said overfill-prevention position, and said valve actuator permitting said valve body to be in said open position when said valve actuator is in said filling position; and said valve actuator urging said valve body toward said closed position when said valve actuator moves from said filling position to said overfill-prevention position, and said valve actuator permitting said valve body to be in said open position when said valve actuator is in said filling position; and a non-contact test mechanism moveable between a service position and a test position, said non-contact test mechanism comprising: a test actuator coupled to said valve actuator such that actuation of said non-contact test mechanism from said service position to said test position advances said valve actuator from said filling position to said overfill-prevention position, whereby said actuation of said non-contact test mechanism urges said valve body toward said closed position with absence of an overfill condition, and said non-contact test mechanism being positioned outside of said conduit (22, 62g) such that said conduit wall is interposed between said test actuator and said fluid path, said test actuator being operable to advance said valve actuator from said filling position to said overfill-prevention position thereby avoiding physically penetrating said conduit wall, whereby said non-contact test mechanism avoids creation of a leak path in said conduit (22, 62g) in order to function as a test mechanism; characterized in that the non-contact test mechanism is disposed upstream of said valve body. a test actuator coupled to said valve actuator such that actuation of said non-contact test mechanism from said service position to said test position advances said valve actuator from said filling position to said overfill-prevention position, whereby said actuation of said non-contact test mechanism urges said valve body toward said closed position with absence of an overfill condition, and said non-contact test mechanism being positioned outside of said conduit (22, 62g) such that said conduit wall is interposed between said test actuator and said fluid path, said test actuator being operable to advance said valve actuator from said filling position to said overfill-prevention position thereby avoiding physically penetrating said conduit wall, whereby said non-contact test mechanism avoids creation of a leak path in said conduit (22, 62g) in order to function as a test mechanism; characterized in that the non-contact test mechanism is disposed upstream of said valve body.