Add a test for fir_filter_bank, and fix bug whereby TimeDimension was…

… built incorrectly

zounds/spectral/functional.py

@@ -109,8 +109,7 @@ def fir_filter_bank(scale, taps, samplerate):
     basis = np.zeros((len(scale), taps))
     basis = ArrayWithUnits(basis, [
         FrequencyDimension(scale),
-        TimeDimension(frequency=samplerate.frequency * taps)
-    ])
+        TimeDimension(*samplerate)])
 
     nyq = samplerate.nyquist
 

zounds/spectral/test_functional.py

@@ -1,7 +1,8 @@
 import numpy as np
 import unittest2
 from functional import \
-    fft, stft, apply_scale, frequency_decomposition, phase_shift, rainbowgram
+    fft, stft, apply_scale, frequency_decomposition, phase_shift, rainbowgram, \
+    fir_filter_bank
 from zounds.core import ArrayWithUnits, IdentityDimension
 from zounds.synthesize import \
     SilenceSynthesizer, TickSynthesizer, SineSynthesizer, FFTSynthesizer
@@ -13,6 +14,22 @@
 from matplotlib import cm
 
 
+class FIRFilterBankTests(unittest2.TestCase):
+    def test_has_correct_dimensions(self):
+        samplerate = SR22050()
+        scale = GeometricScale(
+            start_center_hz=20,
+            stop_center_hz=10000,
+            bandwidth_ratio=0.2,
+            n_bands=100)
+        scale.ensure_overlap_ratio(0.5)
+        taps = 256
+        filter_bank = fir_filter_bank(scale, taps, samplerate)
+        self.assertEqual((len(scale), taps), filter_bank.shape)
+        self.assertEqual(FrequencyDimension(scale), filter_bank.dimensions[0])
+        self.assertEqual(TimeDimension(*samplerate), filter_bank.dimensions[1])
+
+
 class FrequencyDecompositionTests(unittest2.TestCase):
     def test_can_decompose(self):
         sr = SR22050()