docstr: Test behavior for signal without local maxima.
docstr_tok: ["Test","behavior","for","signal","without","local","maxima","."]
code: def test_constant(self, xp, scp):
      """
      Test behavior for signal without local maxima.
      """
      open_interval = (None, None)
      peaks, props = scp.signal.find_peaks(
          xp.ones(10),
          height=open_interval,
          threshold=open_interval,
          prominence=open_interval,
          width=open_interval,
      )
      return (peaks,) + tuple(
          [props[k] for k in self.property_keys if k in props]
      )
  
imports: import pytest
  import cupy
  from cupy.cuda import driver
  from cupy.cuda import runtime
  from cupy import testing
  import cupyx.scipy.signal
  import numpy
label_desc: Use image node_id 1 for calling the TestFindPeaks obj's underlying member method code with example usage: obj.test_constant(xp, scp) and returns: unknown