Issue #19623: Fixed writing to unseekable files in the aifc module.
Fixed writing 'ulaw' (lower case) compressed AIFC files.
diff --git a/Lib/test/test_wave.py b/Lib/test/test_wave.py
index 3e8ef51..9513df4 100644
--- a/Lib/test/test_wave.py
+++ b/Lib/test/test_wave.py
@@ -5,10 +5,15 @@
 import wave
 
 
-class WavePCM8Test(audiotests.AudioWriteTests,
-        audiotests.AudioTestsWithSourceFile,
-        unittest.TestCase):
+class WaveTest(audiotests.AudioWriteTests,
+               audiotests.AudioTestsWithSourceFile):
     module = wave
+    test_unseekable_write = None
+    test_unseekable_overflowed_write = None
+    test_unseekable_incompleted_write = None
+
+
+class WavePCM8Test(WaveTest, unittest.TestCase):
     sndfilename = 'pluck-pcm8.wav'
     sndfilenframes = 3307
     nchannels = 2
@@ -25,10 +30,7 @@
       """)
 
 
-class WavePCM16Test(audiotests.AudioWriteTests,
-        audiotests.AudioTestsWithSourceFile,
-        unittest.TestCase):
-    module = wave
+class WavePCM16Test(WaveTest, unittest.TestCase):
     sndfilename = 'pluck-pcm16.wav'
     sndfilenframes = 3307
     nchannels = 2
@@ -55,10 +57,7 @@
 
 
 
-class WavePCM24Test(audiotests.AudioWriteTests,
-        audiotests.AudioTestsWithSourceFile,
-        unittest.TestCase):
-    module = wave
+class WavePCM24Test(WaveTest, unittest.TestCase):
     sndfilename = 'pluck-pcm24.wav'
     sndfilenframes = 3307
     nchannels = 2
@@ -85,10 +84,7 @@
         frames = audiotests.byteswap3(frames)
 
 
-class WavePCM32Test(audiotests.AudioWriteTests,
-        audiotests.AudioTestsWithSourceFile,
-        unittest.TestCase):
-    module = wave
+class WavePCM32Test(WaveTest, unittest.TestCase):
     sndfilename = 'pluck-pcm32.wav'
     sndfilenframes = 3307
     nchannels = 2