  The flavour symmetry succeeds in explaining the current global fit results.
Flavour-symmetry models can be tested by the future experiments that improve
the precision of neutrino oscillation parameters, \textit{such as} the
MuOn-decay MEdium baseline NeuTrino beam experiment (MOMENT). In this work, we
consider tri-direct littlest seesaw (TDLS) models for a case study, and analyze
how much MOMENT can extend our knowledge on the TDLS model. We find that
measurements of $\theta_{23}$ and $\delta$ are crucial for MOMENT to exclude
the model at more than $5\sigma$ confidence level, if the best fit values in
the last global analysis result is confirmed. Moreover, the $3\sigma$ precision
of model parameters can be improved at MOMENT by at least a factor of two.
Finally, we project the surface at the $3\sigma$ confidence level from the
model-parameter space to the oscillation-parameter space, and find the
potential of MOMENT to observe the sum rule between $\theta_{23}$ and $\delta$
predicted by TDLS.
