Changing Section Numbering Ruins TOC

I am trying to include the word "Appendix" in the section titles before the appendix number. Trying \renewcommand{\thesection}{Appendix \Alph{section}:} works, but messes up the table of contents - the section name is printed over the section number:

Minimal working example:

\documentclass{article}
\begin{document}

\tableofcontents

\section{Intro}
content

\appendix
\renewcommand{\thesection}{Appendix \Alph{section}:}

\section{Test 1}
content

\section{Test 2}
content

\end{document}


Any suggestions much appreciated.

You can load the appendix package and use the appendices environment`. There are two ways to do that, and also other goodies for the table of contents and the header. See the documentation, pp.3-4 for details.