In this work, we test an effective-one-body radiation-reaction force for
eccentric planar orbits of a test mass in a Kerr background, which contains
third-order post-Newtonian (PN) non-spinning and second-order PN spin
contributions. We compare the analytical fluxes connected to two different
resummations of this force, truncated at different PN orders in the eccentric
sector, with the numerical fluxes computed through the use of frequency- and
time-domain Teukolsky-equation codes. We find that the different PN truncations
of the radiation-reaction force show the expected scaling in the weak
gravitational-field regime, and we observe a fractional difference with the
numerical fluxes that is $<5 \%$, for orbits characterized by eccentricity $0
\le e \le 0.7$, central black-hole spin $-0.99 M \le a \le 0.99 M$ and fixed
orbital-averaged quantity $x=\langle M\Omega \rangle^{2/3} = 0.06$,
corresponding to the mildly strong-field regime with semilatera recta $9 M<p<17
M$. Our analysis provides useful information for the development of
spin-aligned eccentric models in the comparable-mass case.
