Added spline in test report

Tests/Test.tex

@@ -444,6 +444,16 @@ $$
 
 \part{Meshing and animation}
 \chapter{Meshing}
+\section{Splines}
+The spline is a mathematical tool to create a smooth curve from a set of
+points. The following test illustrates the fact that our spline is smooth, and
+that the derivative of the splines are computed right.
+\begin{figure}[H]
+    \centering
+    \includegraphics[scale=0.4]{images/splines/spline.png}
+    \caption{A spline blue and its tangent in red}
+\end{figure}
+
 \section{Meshing the extremities}
 \paragraph{} In our mesh the extremities refer to the extrem points of splines which are not part of a junction.
 Meshing the extremities consists in two steps : build each extremity and subdivise it. In order to build the extremities,