"""These are tests for the feedback function in rlocus.py."""

@pytest.fixture(params=[pytest.param((sysclass, sargs + (dt, )),

def sys(self, request):

"""Return some simple LTI systems for testing"""

# avoid construction during collection time: prevent unfiltered

# deprecation warning

sysfn, args = request.param

return sysfn(*args)

def check_cl_poles(self, sys, pole_list, k_list):

for k, poles in zip(k_list, pole_list):

poles_expected = np.sort(feedback(sys, k).poles())

poles = np.sort(poles)

np.testing.assert_array_almost_equal(poles, poles_expected)

def testRootLocus(self, sys):

"""Basic root locus (no plot)"""

klist = [-1, 0, 1]

roots, k_out = root_locus(sys, klist, plot=False)

np.testing.assert_equal(len(roots), len(klist))

np.testing.assert_allclose(klist, k_out)

self.check_cl_poles(sys, roots, klist)

# now check with plotting

roots, k_out = root_locus(sys, klist)

np.testing.assert_equal(len(roots), len(klist))

np.testing.assert_allclose(klist, k_out)

self.check_cl_poles(sys, roots, klist)

def test_without_gains(self, sys):

roots, kvect = root_locus(sys, plot=False)

self.check_cl_poles(sys, roots, kvect)

@pytest.mark.slow

@pytest.mark.parametrize('grid', [None, True, False])

def test_root_locus_plot_grid(self, sys, grid):

rlist, klist = root_locus(sys, grid=grid)

ax = plt.gca()

n_gridlines = sum([int(line.get_linestyle() in [':', 'dotted',

'--', 'dashed'])

for line in ax.lines])

if grid is False:

assert n_gridlines == 2

else:

assert n_gridlines > 2

# TODO check validity of grid

def test_root_locus_warnings(self):

sys = TransferFunction([1000], [1, 25, 100, 0])

with pytest.warns(FutureWarning, match="Plot.*deprecated"):

rlist, klist = root_locus(sys, Plot=True)

with pytest.warns(FutureWarning, match="PrintGain.*deprecated"):

rlist, klist = root_locus(sys, PrintGain=True)

def test_root_locus_neg_false_gain_nonproper(self):

""" Non proper TranferFunction with negative gain: Not implemented"""

with pytest.raises(ValueError, match="with equal order"):

root_locus(TransferFunction([-1, 2], [1, 2]))

# TODO: cover and validate negative false_gain branch in _default_gains()

@pytest.mark.skipif(plt.get_current_fig_manager().toolbar is None,

def test_root_locus_zoom(self):

"""Check the zooming functionality of the Root locus plot"""

system = TransferFunction([1000], [1, 25, 100, 0])

plt.figure()

root_locus(system)

fig = plt.gcf()

ax_rlocus = fig.axes[0]

event = type('test', (object,), {'xdata': 14.7607954359,

'ydata': -35.6171379864,

'inaxes': ax_rlocus.axes})()

ax_rlocus.set_xlim((-10.813628105112421, 14.760795435937652))

ax_rlocus.set_ylim((-35.61713798641108, 33.879716621220311))

plt.get_current_fig_manager().toolbar.mode = 'zoom rect'

_RLClickDispatcher(event, system, fig, ax_rlocus, '-')

zoom_x = ax_rlocus.lines[-2].get_data()[0][0:5]

zoom_y = ax_rlocus.lines[-2].get_data()[1][0:5]

zoom_y = [abs(y) for y in zoom_y]

zoom_x_valid = [

-5., - 4.61281263, - 4.16689986, - 4.04122642, - 3.90736502]

zoom_y_valid = [0., 0., 0., 0., 0.]

assert_array_almost_equal(zoom_x, zoom_x_valid)

assert_array_almost_equal(zoom_y, zoom_y_valid)

@pytest.mark.timeout(2)

def test_rlocus_default_wn(self):

"""Check that default wn calculation works properly"""

#

# System that triggers use of y-axis as basis for wn (for coverage)

#

# This system generates a root locus plot that used to cause the

# creation (and subsequent deletion) of a large number of natural

# frequency contours within the `_default_wn` function in `rlocus.py`.

# This unit test makes sure that is fixed by generating a test case

# that will take a long time to do the calculation (minutes).

#

import scipy as sp

import signal

# Define a system that exhibits this behavior

sys = ct.tf(*sp.signal.zpk2tf(

[-1e-2, 1-1e7j, 1+1e7j], [0, -1e7j, 1e7j], 1))