add explicit interpolation: interp(); fix tests to use new API

audio_analysis/tools.py

@@ -3,6 +3,7 @@
 import bokeh.plotting
 import bokeh.models
 import pandas
+import scipy.interpolate
 
 
 def new_data(x, xlabel, y, ylabel):
@@ -24,7 +25,7 @@ def plot(self, fig=None, legend=None, color=None):
                                         sizing_mode='stretch_both')
             # increase the limit for sci. notation on x-axis
             fig.xaxis.formatter = bokeh.models.BasicTickFormatter(power_limit_high=6)
-            if self._x2_factor is not None:
+            if hasattr(self, '_x2_factor'):
                 x2_ax = bokeh.models.LinearAxis(axis_label=self._x2_label)
                 js_code = "return Math.round(tick * %f * 100) / 100" % self._x2_factor
                 x2_ax.formatter = bokeh.models.FuncTickFormatter(code=js_code)
@@ -33,10 +34,13 @@ def plot(self, fig=None, legend=None, color=None):
         return fig
 
     def add_x_axis(self, factor, label):
-        assert self._x2_factor is None, 'only 2 x-axis possible' 
+        assert not hasattr(self, '_x2_factor'), 'only 2 x-axis possible'
         self._x2_factor = factor
         self._x2_label = label
 
+    def interp(self, x, kind='linear'):
+        return scipy.interpolate.interp1d(self.index, self, kind)(x)
+
 
 def _dbfs(sq):
     return 10 * np.log10(sq * 2)  # +3dB, dBFS sine scaling

tests/test_audio.py

@@ -35,7 +35,7 @@ def test_spectrum(file):
     ch = 0
     pcm = audio.PCMArray(os.path.join(here, file))[ch]
     s = tools.spectrum(pcm)
-    assert abs(s[hz] - dbfs) < TOLERANCE_DB
+    assert abs(s.interp(hz) - dbfs) < TOLERANCE_DB
 
 
 @pytest.mark.parametrize('file', FILES.keys())
@@ -44,6 +44,6 @@ def test_power(file):
     ch = 0
     pcm = audio.PCMArray(os.path.join(here, file))[ch]
     p = tools.power(pcm, window=1023)
-    assert all(abs(p.y - dbfs) < TOLERANCE_DB + .1)
-    assert abs(p.y.mean() - dbfs) < TOLERANCE_DB
+    assert all(abs(p - dbfs) < TOLERANCE_DB + .1)
+    assert abs(p.mean() - dbfs) < TOLERANCE_DB