diff --git a/tests/environments/groupthm/test2.tex b/tests/environments/groupthm/test2.tex
new file mode 100644
index 0000000..6a4064c
--- /dev/null
+++ b/tests/environments/groupthm/test2.tex
@@ -0,0 +1,216 @@
+\documentclass{article}
+
+\usepackage{amsmath}
+\usepackage{mdframed}
+\usepackage{amsthm}
+\usepackage{thmtools}
+\usepackage{mkessler-hypersetup}
+\usepackage{verbatim}
+
+\usepackage{mkessler-refproof}
+
+
+\def\cname#1{\texttt{$\backslash$#1}}
+
+
+
+\NewDocumentEnvironment{remark}{!s o}
+
+
+\newcounter{all}
+
+\declaretheorem[sibling = all]{definition}
+
+\declaretheorem[sibling = all, name = Theorem ]{intntheorem}
+\declaretheorem[sibling = all, name = Theorem*]{intstheorem}
+\declaretheorem[sibling = all, name = Theorem$^{\dagger}$]{intdtheorem}
+
+\declaretheorem[sibling = all, parent = section ]{testthm}
+\declaretheorem[sibling = all, parent = section ]{lemma}
+
+\NewDocumentEnvironment{theorem}{ !s !t+ }
+{
+  \IfBooleanTF{#1}
+  {
+    \begin{intstheorem}
+  }
+  {
+    \IfBooleanTF{#2}
+    {
+      \begin{intdtheorem}
+    }
+    {
+      \begin{intntheorem}
+    }
+  }
+}
+{
+  \IfBooleanTF{#1}
+  {
+    \end{intstheorem}
+  }
+  {
+    \IfBooleanTF{#2}
+    {
+      \end{intdtheorem}
+    }
+    {
+      \end{intntheorem}
+    }
+  }
+}
+
+\addtotheorempreheadhook{test}
+\addtotheorempostheadhook{test}
+
+\begin{document}
+
+\section{What we need}
+\subsection{Groups / classes of theorems}
+These share some properties and are controlled via options.
+
+Things an environment should change dynamically:
+\begin{itemize}
+  \item parent, sibling
+  \item title: variants with * or $^{\dagger}$
+\end{itemize}
+
+\subsection{Greater Syntax for theorems}
+Expand the \cname{NewDocumentEnvironment}-like syntax to theorems as well.
+
+\subsection{Example Code}
+
+\begin{verbatim}
+  \NewTheoremGroup { all }
+  [
+  ]
+
+  \NewTheoremGroup { big }
+  [
+    thmtools = { sibling = insection }
+  ]
+
+  \NewTheoremGroup { dagger }
+  [
+    postname = { $\dagger$ },
+    thmtools = { sibling = insubsection }
+  ]
+
+  \NewTheoremGroup { small }
+  [
+    thmtools = { sibling = insubsection }
+  ]
+
+  \NewTheoremGroup { star }
+  [
+    thmtools = { sibling = insubsection },
+    postname = { * }
+  ]
+
+  \NewTheoremGroup { starred }
+  [
+    thmtools = { numbered = no }
+  ]
+
+  \DeclareTheoremVariants { theorem } { !s !t+ o}
+  {
+    \AddTheoremToGroup { big }
+    \IfBooleanT {#1} { \AddTheoremToGroup{star}     }
+    \IfBooleanT {#2} { \AddTheoremToGroup{daggered} }
+  }
+\end{verbatim}
+
+\subsection{Syntax}
+
+\begin{verbatim}
+  \NewTheoremGroup {<name>}
+  [
+    thmtools = {<options passed to thmtools>},
+    prename  = <inserted before name>,
+    postname = <inserted after name>,
+    mapname  = <applied to name as function>,
+  ]
+
+  \NewGroupedTheorem
+  [
+    thmtools = {<options passed to thmtools>},
+    group    = {<comma separated list of groups}
+  ]
+  {<name>}
+
+  \NewDocumentTheorem{<name>}{<signature>}
+  {
+    any legal xparse code that issues the commands
+    \AddTheoremToGroup{<groupname>}
+    and
+    \PassToThmtools{<comma separated list>}
+    \PassAsOptionalArgument{<token list>}
+  }
+
+\end{verbatim}
+Last case: For the powerset of the mentioned theorems, generate internal theorem variants,
+that are part of the corresponding groups, where in the document, the signature will be 
+calling the corresponding theorem variant automatically.
+
+
+A typical declaration would thus be:
+\begin{verbatim}
+  \NewDocumentTheorem{theorem}{ !s !t+ o}
+  {
+    \IfBooleanT{#1}{ \AddTheoremToGroup{star}   }
+    \IfBooleanT{#2}{ \AddTheoremToGroup{dagger} }
+    \PassAsOptionalArgument{#3}
+  }
+\end{verbatim}
+
+
+\section{Testing}
+\begin{theorem}\label{normal}
+ test 
+\end{theorem}
+
+\begin{theorem}*\label{star}
+
+\end{theorem}
+
+\begin{theorem}+[comment]\label{dagger}
+  test
+\end{theorem}
+
+\def\foo#1.#2ab#3.\end{foo: #1 #2 #3}
+
+\foo 1.2ab3.\end
+
+\section{test}\label{sec}
+
+\section*{test}
+\phantomsection\label{sec2}
+
+\autoref{sec}
+
+\autoref{sec2}
+
+\begin{theorem}
+\end{theorem}
+
+\autoref{test}
+
+\begin{theorem}[test]
+  bla
+\end{theorem}
+
+\begin{definition}
+  
+\end{definition}
+
+normal:~\autoref{normal}, star:~\autoref{star}, dagger:~\autoref{dagger} 
+
+\begin{testthm}
+  
+\end{testthm}
+
+\begin{lemma}
+  bla
+\end{lemma}
+
+\end{document}
diff --git a/tests/utils/powerset/test.tex b/tests/utils/powerset/test.tex
new file mode 100644
index 0000000..6acc613
--- /dev/null
+++ b/tests/utils/powerset/test.tex
@@ -0,0 +1,82 @@
+\documentclass{article}
+
+
+\ExplSyntaxOn
+
+
+\clist_new:N \copied_clist
+\seq_new:N \saved_seq
+
+%remove left  -> push on stack
+% call recursive
+% add left to 'extra'
+% call recursive
+% remove left from 'extra'
+% add from stack to left
+
+
+\cs_generate_variant:Nn \clist_remove_all:Nn { N V }
+
+\cs_new:Npn \clist_use_powerset_aux:Nn #1 #2 
+{
+  \clist_if_empty:NTF \copied_clist
+    {
+      #2
+    }
+    {
+
+      \clist_get:NN \copied_clist \l_tmpa_tl % gets first element of copied list into local
+      \seq_push:NV \saved_seq \l_tmpa_tl     % pushes local value onto stack
+      \clist_pop:NN \copied_clist { \l_tmpa_tl } % removes from copied list
+
+      \clist_use_powerset_aux:Nn #1 {#2}
+      
+      \seq_get:NN \saved_seq \l_tmpa_tl
+      \clist_put_left:NV #1 \l_tmpa_tl
+
+      \clist_use_powerset_aux:Nn #1 {#2}
+
+      \seq_get:NN \saved_seq \l_tmpa_tl
+      \clist_remove_all:NV #1 \l_tmpa_tl
+      \clist_push:NV \copied_clist \l_tmpa_tl
+      \seq_pop:NN \saved_seq \l_tmpa_tl
+    }
+}
+
+\cs_new:Npn \clist_use_powerset:Nn #1 #2
+{
+  \clist_set_eq:NN \copied_clist #1
+  \clist_clear:N #1
+  \clist_remove_duplicates:N \copied_clist
+
+  \clist_use_powerset_aux:Nn #1 {#2}
+
+  \clist_set_eq:NN #1 \copied_clist
+}
+
+\clist_new:N  \test_clist
+\tl_set:Nn \test_clist {1,2,3,4,5,6,7,8,9}
+
+\def\foo {
+  \clist_use_powerset:Nn \test_clist
+    {
+%      reached~end:~
+%      \clist_use:Nn \test_clist  {,} \newline
+      \stepcounter{testval}
+    }
+  \test_clist
+}
+
+\ExplSyntaxOff
+
+
+\begin{document}
+
+\newcounter{testval}
+
+
+\noindent \foo
+
+\thetestval
+
+\end{document}