plot_piecewise(Heaviside(x, 0).rewrite(Piecewise),
    (x, -10, 10), dots=False)
# Expected:
## Plot object containing:
## [0]: cartesian line: 0 for x over (-10, 0)
## [1]: cartesian line: 1 for x over (1.00000000000000e-6, 10)