animtest and codetest are two identical unused areas in Pikmin. Given their names and simplicity, there were likely meant to test animations during the game's development.
Geography
The entire area is just one fairly large green and light green checkerboard that is completely flat. Along the floor is some text in English and Japanese. The English lines read "piki park", and the Japanese text is the same.
A video showing the map: {{#ev:youtube|RFuDtXo3DYE}}