Issue 470, reading past audio file EOF (#476)

* create better error message when we read past the end of an audio file

* add a working example

* download crunching.mp3

moviepy/audio/io/readers.py

@@ -185,7 +185,11 @@ def get_frame(self, tt):
                 result[in_time] = self.buffer[indices]
                 return result
             except IndexError as error:
-                raise IOError("Error in file %s, "%(self.filename)+
+                if indices.max() > len(self.buffer):
+                   raise IOError("Error reading file '%s', " % self.filename +
+                                 "trying to access beyond the end of the file")
+                else:
+                   raise IOError("Error in file %s, "%(self.filename)+
                        "At time t=%.02f-%.02f seconds, "%(tt[0], tt[-1])+
                        "indices wanted: %d-%d, "%(indices.min(), indices.max())+
                        "but len(buffer)=%d\n"%(len(self.buffer))+ str(error))

tests/download_media.py

@@ -28,3 +28,6 @@ def download():
 
     download_url("https://github.com/earney/moviepy_media/raw/master/tests/videos/big_buck_bunny_432_433.webm",
                  "media/big_buck_bunny_432_433.webm")
+
+    download_url("https://github.com/earney/moviepy_media/raw/master/tests/sounds/crunching.mp3",
+                 "media/crunching.mp3")

tests/test_issues.py

@@ -91,5 +91,19 @@ def test_issue_467():
     #caused an error, NameError: global name 'copy' is not defined
     clip = clip.fx(vfx.blink, d_on=1, d_off=1)
 
+def test_issue_470():
+    audio_clip = AudioFileClip('media/crunching.mp3')
+
+    # t_end is out of bounds
+    subclip = audio_clip.subclip(t_start=6, t_end=9)
+
+    with pytest.raises(IOError, message="Expecting IOError"):
+         subclip.write_audiofile('/tmp/issue_470.wav', write_logfile=True)
+
+    #but this one should work..
+    subclip = audio_clip.subclip(t_start=6, t_end=8)
+    subclip.write_audiofile('/tmp/issue_470.wav', write_logfile=True)
+
+
 if __name__ == '__main__':
    pytest.main()