# Tikz node with multiparts coloring but single part text

I want to create a tikz node with two colors (split along a vertical axis) and a single body of text spanning the two parts.

The way I've seen the shapes.multipart library used makes the being confined to a single part of the node, or to write multiple distinct text bodies in the different part whereas I'm looking to share the text.

I could manually do it by creating two nodes at the same coordinates, one containing the text and the other one a multipart node filled in two colors, but if I do it the simple way the dimensions of the multipart node wouldn't adapt to the text size and so the text might overflow from the whole node.

There's no need for a multipart node. A regular node can be filled with several colors with path picture command.

\documentclass[tikz,border=2mm]{standalone}

\begin{document}
\begin{tikzpicture}
\node[fill=green!30, path picture={\fill[red!30] (path picture bounding box.west) rectangle (path picture bounding box.north east);}] (a) {This is a node};

\node[fill=green!30, path picture={\fill[red!30] (path picture bounding box.south west) --  (path picture bounding box.north east)-|cycle;}] at (0,-1) {This is a node};

\end{tikzpicture}
\end{document}