add UT for recv.py

amodem/recv.py

@@ -48,7 +48,6 @@ def report_carrier(bufs, begin):
 
 
 def detect(samples, freq):
-
     counter = 0
     bufs = collections.deque([], maxlen=config.baud)  # 1 second of symbols
     for offset, buf in common.iterate(samples, config.Nsym):

tests/test_recv.py

@@ -0,0 +1,28 @@
+from amodem import config, recv, train
+import numpy as np
+
+def test_detect():
+    P = sum(train.prefix)
+    t = np.arange(P * config.Nsym) * config.Ts
+    x = np.cos(2 * np.pi * config.Fc * t)
+    samples, amp = recv.detect(x, config.Fc)
+    assert abs(1 - amp) < 1e-12
+
+    x = np.cos(2 * np.pi * (2*config.Fc) * t)
+    try:
+        recv.detect(x, config.Fc)
+        assert False
+    except ValueError:
+        pass
+
+def test_prefix():
+    symbols = [[i] for i in train.prefix]
+    freq_err, phase_err = recv.receive_prefix(symbols)
+    assert freq_err == 0
+    assert phase_err == 0
+
+    try:
+        recv.receive_prefix([[0]] * len(train.prefix))
+        assert False
+    except ValueError:
+        pass