  Testing the so-called consistency relations plays an important role for
distinguishing the different classes of inflation models. In this paper, we
investigate the possible testing based on the potential observations of the
cosmic microwave background (CMB) radiation, including the planned CMBPol
mission and the ideal CMB experiment where only the reduced cosmic weak lensing
contamination for the B-mode polarization is considered. We find that for the
canonical single-field inflation and the phantom inflation, the consistency
relations are quite hard to be tested: the testing is possible only if $r>0.14$
for CMBPol mission, and $r>0.06$ for the ideal experiment. However, the
situation could become much better for the general Lorentz invariant
single-field inflation with large non-gaussian signal and the two-field
inflation with strong correlation between the adiabatic and the isocurvature
perturbations. We find that for these two classes of inflation the testing is
possible if $r\gtrsim 10^{-2}$ or even smaller for both CMB experiments.
