python/tests/test_pitchshift.py: add minimal tests

diff --git a/python/tests/test_pitchshift.py b/python/tests/test_pitchshift.py
new file mode 100755 (executable)
index 0000000..940124f
--- /dev/null
+++ b/python/tests/test_pitchshift.py
@@ -0,0 +1,43 @@
+#! /usr/bin/env python
+
+from nose2 import TestCase
+import aubio
+
+class aubio_pitchshift(TestCase):
+
+    def setUp(self):
+        self.o = aubio.pitchshift()
+
+    def test_default_creation(self):
+        self.assertEqual(self.o.get_pitchscale(), 1)
+        self.assertEqual(self.o.get_transpose(), 0)
+
+    def test_on_zeros(self):
+        test_length = 20000
+        read = 0
+        # test on zeros
+        vec = aubio.fvec(512)
+        transpose_range = 24
+        while read < test_length:
+            # transpose the samples
+            out = self.o(vec)
+            self.assertTrue((out == 0).all())
+            # position in the file (between 0. and 1.)
+            percent_read = read / float(test_length)
+            # variable transpose rate (in semitones)
+            transpose = 2 * transpose_range * percent_read - transpose_range
+            # set transpose rate
+            self.o.set_transpose(transpose)
+            read += len(vec)
+
+    def test_transpose_too_high(self):
+        with self.assertRaises(ValueError):
+            self.o.set_transpose(24.3)
+
+    def test_transpose_too_low(self):
+        with self.assertRaises(ValueError):
+            self.o.set_transpose(-24.3)
+
+if __name__ == '__main__':
+    from nose2 import main
+    main()