Custom frametitle with logo in fixed position and multi-line title

Question

TL;DR: How can I include a logo in the frame title at a fixed position with two-line titles wrapping around it?

I am creating a custom beamertheme. The frametitle has to include a logo in the top right corner and needs to be able to deal with frame titles that span two lines. Maybe I'm missing something obvious, but I can't seem to get it right.

I have used this blog entry by Matthias Vogelgesang to create most of the custom frametitle:

\setbeamertemplate{frametitle}
{%
    \nointerlineskip
    \begin{beamercolorbox}[sep=0.3cm,wd=\paperwidth]{frametitle}
        \usebeamerfont{frametitle}%
        \vbox{}\vskip-1ex%
        \strut\insertframetitle\strut%
        \hfill
        \raisebox{-0.8mm}{\includegraphics[width=2cm,,height=0.4cm]{example-image}}
        \vskip-0.8ex%
    \end{beamercolorbox}
}

This would deal with longer frametitles by shifting the logo downwards:

So far I have managed to include the logo at a fixed postition using this answer by Gonzalo Medina, by removing \raisebox{-0.8mm}{\includegraphics[width=2cm,,height=0.4cm]{example-image}} from the frametitle definition and adding this to my document:

\addtobeamertemplate{frametitle}{}{%
\begin{tikzpicture}[remember picture,overlay]
    \node[anchor=north east,yshift=-0.05cm] at (current page.north east) {\includegraphics[width=2cm,height=0.4cm]{example-image}};
\end{tikzpicture}}

However, a longer frame title does not wrap at the image, it simply goes past it:

Is there a way to keep the logo at its position and still get longer titles to respect the logos boundaries?

MWE: (\usetheme{Test1} for first example, \usetheme{Test2} for second example)

\documentclass[10pt,dvipsnames]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}

\usepackage{filecontents}

\begin{filecontents}{beamerthemeTest1.sty}
    \setbeamerfont{frametitle}{size=\large}
    \setbeamercolor{frametitle}{fg=JungleGreen,bg=Dandelion!60}
    \setbeamertemplate{frametitle}
    {%
        \nointerlineskip
        \begin{beamercolorbox}[sep=0.3cm,wd=\paperwidth]{frametitle}
            \usebeamerfont{frametitle}%
            \vbox{}\vskip-1ex%
            \strut\insertframetitle\strut%
            \hfill
            \raisebox{-0.8mm}{\includegraphics[width=2cm,height=0.4cm]{example-image}}
            \vskip-0.8ex%
        \end{beamercolorbox}
    }
\end{filecontents}

\begin{filecontents}{beamerthemeTest2.sty}
    \setbeamerfont{frametitle}{size=\large}
    \setbeamercolor{frametitle}{fg=JungleGreen,bg=Dandelion!60}
    \setbeamertemplate{frametitle}
    {%
        \nointerlineskip
        \begin{beamercolorbox}[sep=0.3cm,wd=\paperwidth]{frametitle}
            \usebeamerfont{frametitle}%
            \vbox{}\vskip-1ex%
            \strut\insertframetitle\strut%
            \hfill
            \vskip-0.8ex%
        \end{beamercolorbox}
    }
    \addtobeamertemplate{frametitle}{}{%
        \begin{tikzpicture}[remember picture,overlay]
        \node[anchor=north east,yshift=-0.05cm] at (current page.north east) {\includegraphics[width=2cm,height=0.4cm]{example-image}};
        \end{tikzpicture}}
\end{filecontents}

\usetheme{Test1}
%\usetheme{Test2}

\begin{document}

\begin{frame}{Test Frame}
    Optional Content
\end{frame}

\begin{frame}{Test Frame With Really Really Really Really Really Really Long Title}
    Optional Content
\end{frame}

\begin{frame}{Test Frame With Really Really Really Really Really Really Really Really Really Long Title}
    Optional Content
\end{frame}

\end{document}

Answer 1

Does adding rightskip=2cm to the option list of beamercolorbox in your beamerThemeTest2.sty fulfill your expectations?

Line 31 of your MWE thus looks like this:

\begin{beamercolorbox}[sep=0.3cm,rightskip=2cm,wd=\paperwidth]{frametitle}

That way, the text stays out of the image. I have not checked whether the vertical margins remain the same, though.

Answer 2

In your second theme, you could place the title in some element of which you can control the width, e.g. a \parbox or a minipage

(the .8\textwidth are just a quick guess, you might have to fine tune it a bit)

\documentclass[10pt,dvipsnames]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}

\usepackage{filecontents}
\begin{filecontents*}{beamerthemeTest2.sty}
    \setbeamerfont{frametitle}{size=\large}
    \setbeamercolor{frametitle}{fg=JungleGreen,bg=Dandelion!60}
    \setbeamertemplate{frametitle}
    {%
        \nointerlineskip
        \begin{beamercolorbox}[sep=0.3cm,wd=\paperwidth]{frametitle}
            \usebeamerfont{frametitle}%
            \vbox{}\vskip-1ex%
            \parbox{.8\textwidth}{\strut\insertframetitle\strut}%
            \hfill
            \vskip-0.8ex%
        \end{beamercolorbox}
    }
    \addtobeamertemplate{frametitle}{}{%
        \begin{tikzpicture}[remember picture,overlay]
        \node[anchor=north east,yshift=-0.05cm] at (current page.north east) {\includegraphics[width=2cm,height=0.4cm]{example-image}};
        \end{tikzpicture}}
\end{filecontents*}

\usetheme{Test2}

\begin{document}

\begin{frame}{Test Frame}
    Optional Content
\end{frame}

\begin{frame}{Test Frame With Really Really Really Really Really Really Long Title}
    Optional Content
\end{frame}

\begin{frame}{Test Frame With Really Really Really Really Really Really Really Really Really Long Title}
    Optional Content
\end{frame}

\end{document}