TST: added a test condition that expects the warning to be issued when the Nyquist frequency is reached

forgi86 · forgi86 · commit 81f9ee7657e5 · 2021-04-03T00:59:01.000+02:00
FIX: changed &gt;= to &gt; to issue Nyquist frequency warning
diff --git a/control/freqplot.py b/control/freqplot.py
@@ -1133,8 +1133,8 @@ def singular_values_plot(syslist, omega=None,
                 omega_sys = np.hstack((
                     omega_sys[omega_sys < nyquistfrq], nyquistfrq))
             else:
-                if np.max(omega_sys) >= nyquistfrq:
-                    warnings.warn("Specified frequency range is above Nyquist limit!")
+                if np.max(omega_sys) > nyquistfrq:
+                    warnings.warn("evaluation above Nyquist frequency")
 
             omega_complex = np.exp(1j * omega_sys * sys.dt)
         else:
diff --git a/control/tests/freqresp_test.py b/control/tests/freqresp_test.py
@@ -619,8 +619,7 @@ def test_singular_values_plot_mpl_base(ss_mimo_ct, ss_mimo_dt):
     sys_ct = ss_mimo_ct.sys
     sys_dt = ss_mimo_dt.sys
     plt.figure()
-    omega_all = np.logspace(-3, 2, 1000)
-    singular_values_plot(sys_ct, omega_all, plot=True)
+    singular_values_plot(sys_ct, plot=True)
     fig = plt.gcf()
     allaxes = fig.get_axes()
     assert(len(allaxes) == 1)
@@ -636,9 +635,11 @@ def test_singular_values_plot_mpl_base(ss_mimo_ct, ss_mimo_dt):
 def test_singular_values_plot_mpl_superimpose_nyq(ss_mimo_ct, ss_mimo_dt):
     sys_ct = ss_mimo_ct.sys
     sys_dt = ss_mimo_dt.sys
+    omega_all = np.logspace(-3, 2, 1000)
     plt.figure()
-    singular_values_plot(sys_ct, plot=True)
-    singular_values_plot(sys_dt, plot=True)
+    singular_values_plot(sys_ct, omega_all, plot=True)
+    with pytest.warns(UserWarning):
+        singular_values_plot(sys_dt, omega_all, plot=True)
     fig = plt.gcf()
     allaxes = fig.get_axes()
     assert(len(allaxes) == 1)
