  We test both the FLRW geometry and $\Lambda$CDM cosmology in a model
independent way by reconstructing the Hubble function $H(z)$, the comoving
distance $D(z)$ and the growth of structure $f\sigma_8(z)$ using the most
recent data available. We use the linear model formalism in order to optimally
reconstruct the latter cosmological functions, together with their derivatives
and integrals. We then evaluate four of the null tests available in literature:
$Om_{1}$ by Sahni et al., $Om_{2}$ by Zunckel \& Clarkson, $Ok$ by Clarkson et
al., and $ns$ by Nesseris \& Sapone. For all the four tests we find agreement,
within the errors, with the standard cosmological model.
