raise value error and add unittest

Author: helion-du-mas-des-bourboux-thales

commpy/sequences.py

@@ -94,11 +94,16 @@ def zcsequence(u, seq_length, q=0):
     zcseq : 1D ndarray of complex floats
         ZC sequence generated.
     """
-    assert u>0
-    assert u<seq_length
-    assert np.gcd(u,seq_length)==1
+
     for el in [u,seq_length,q]:
-        assert float(el).is_integer()
+        if not float(el).is_integer():
+            raise ValueError('{} is not an integer'.format(el))
+    if u<=0:
+        raise ValueError('u is not stricly positive')
+    if u>=seq_length:
+        raise ValueError('u is not stricly smaller than seq_length')
+    if np.gcd(u,seq_length)!=1:
+        raise ValueError('the greatest common denominator of u and seq_length is not 1')
 
     cf = seq_length%2
     n = np.arange(seq_length)

commpy/tests/test_sequences.py

@@ -1,16 +1,17 @@
 # Authors: CommPy contributors
 # License: BSD 3-Clause
 
+import numpy as np
 from numpy import array
-from numpy.testing import run_module_suite, assert_raises, assert_equal
-
-from commpy.sequences import pnsequence
+from numpy.testing import run_module_suite, assert_raises, assert_equal, assert_almost_equal
 
+from commpy.sequences import pnsequence, zcsequence
 
 def test_pnsequence():
     # Test the raises of errors
     with assert_raises(ValueError):
         pnsequence(4, '001', '1101', 2**4 - 1)
+    with assert_raises(ValueError):
         pnsequence(4, '0011', '110', 2 ** 4 - 1)
 
     # Test output with
@@ -19,6 +20,34 @@ def test_pnsequence():
     assert_equal(pnsequence(4, (0, 0, 1, 1), array((1, 1, 0, 1)), 7), array((1, 1, 0, 0, 1, 0, 1), int),
                  err_msg='Pseudo-noise sequence is not the one expected.')
 
+def test_zcsequence():
+    # Test the raises of errors
+    with assert_raises(ValueError):
+        zcsequence(u=-1, seq_length=20, q=0)
+    with assert_raises(ValueError):
+        zcsequence(u=20, seq_length=0, q=0)
+    with assert_raises(ValueError):
+        zcsequence(u=3, seq_length=18, q=0)
+    with assert_raises(ValueError):
+        zcsequence(u=3.1, seq_length=11, q=0)
+    with assert_raises(ValueError):
+        zcsequence(u=3, seq_length=11.1, q=0)
+    with assert_raises(ValueError):
+        zcsequence(u=3, seq_length=11, q=0.1)
+
+    # Test output with
+    assert_almost_equal(zcsequence(u=1, seq_length=2, q=0), array([1.000000e+00+0.j, 6.123234e-17-1.j]),
+        err_msg='CAZAC sequence is not the expected one.')
+
+    # Test if output cross-correlation is valid
+    seqCAZAC = zcsequence(u=3, seq_length=20, q=0)
+    x = np.fft.fft(seqCAZAC) / np.sqrt(seqCAZAC.size)
+    h = (np.fft.ifft(np.conj(x) * x)*np.sqrt(seqCAZAC.size)).T
+    corr = np.absolute(h)**2/h.size
+    assert_almost_equal(corr[0], 1.,
+        err_msg='CAZAC sequence auto-correlation is not valid, first term is not 1')
+    assert_almost_equal(corr[1:], np.zeros(corr.size-1),
+        err_msg='CAZAC sequence auto-correlation is not valid, all terms except first are not 0')
 
 if __name__ == "__main__":
     run_module_suite()