diff --git a/converters/base.py b/converters/base.py
index b8dc0bb..83d5702 100755
--- a/converters/base.py
+++ b/converters/base.py
@@ -157,6 +157,7 @@ class Converter(Configurable):
         self.exclude_cells = exclude
         self.infile = infile
         if infile:
+            self.infile = infile
             self.infile_dir, infile_root = os.path.split(infile)
             self.infile_root = os.path.splitext(infile_root)[0]
             self.clean_name = clean_filename(self.infile_root)
@@ -327,7 +328,6 @@ class Converter(Configurable):
 
         # Is it an image?
         if fmt in ['png', 'svg', 'jpg', 'pdf'] and self.extract_figures:
-            print('I will extract this', fmt)
             img_file = self._new_figure(output[fmt], fmt)
             # Subclasses can have format-specific render functions (e.g.,
             # latex has to auto-convert all SVG to PDF first).
@@ -336,7 +336,6 @@ class Converter(Configurable):
                 lines_fun = self._img_lines
             lines = lines_fun(img_file)
         else:
-            print('I will NOT extract this', fmt)
             lines_fun = self.dispatch_display_format(fmt)
             lines = lines_fun(output)
 
diff --git a/converters/notebook.py b/converters/notebook.py
index c4e970a..32cab8c 100755
--- a/converters/notebook.py
+++ b/converters/notebook.py
@@ -44,8 +44,8 @@ class ConverterNotebook(Converter):
     """
     extension = 'ipynb'
 
-    def __init__(self, infile, outbase, **kw):
-        Converter.__init__(self, infile, **kw)
+    def __init__(self, infile=None, outbase=None, **kw):
+        Converter.__init__(self, infile=infile, **kw)
         self.outbase = outbase
         rmtree(self.files_dir)
 
diff --git a/nbconvert.py b/nbconvert.py
index 36f8015..5769bc0 100755
--- a/nbconvert.py
+++ b/nbconvert.py
@@ -108,7 +108,8 @@ class NbconvertApp(Application):
     def run(self):
         """Convert a notebook to html in one step"""
         ConverterClass = converters[self.fmt]
-        converter = ConverterClass(infile=self.extra_args[0],  config=self.config)
+        infile = (self.extra_args or [None])[0]
+        converter = ConverterClass(infile=infile,  config=self.config)
         converter.render()
 
 def main():
diff --git a/tests/test_nbconverter.py b/tests/test_nbconverter.py
index 1718f47..a82d243 100644
--- a/tests/test_nbconverter.py
+++ b/tests/test_nbconverter.py
@@ -17,9 +17,9 @@ def test_roundtrip():
     out2 = os.path.join(directory, outbase2)
     fname = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                          'test.ipynb')
-    converter = ConverterNotebook(fname, out1)
+    converter = ConverterNotebook(infile=fname, outbase=out1)
     converter.render()
-    converter2 = ConverterNotebook(out1 + '.ipynb', out2)
+    converter2 = ConverterNotebook(infile=out1 + '.ipynb', outbase=out2)
     converter2.render()
 
     with open(out1 + '.ipynb', 'rb') as f:
diff --git a/tests/test_references.py b/tests/test_references.py
index 713151d..36414c3 100644
--- a/tests/test_references.py
+++ b/tests/test_references.py
@@ -50,7 +50,7 @@ def compfiles(stra, strb):
 
 @nottest
 def test_conversion(ConverterClass, ipynb, ref_file):
-    converter = ConverterClass(ipynb)
+    converter = ConverterClass(infile=ipynb)
     converter.read()
     cv = converter.convert()
     with io.open(ref_file) as ref:
diff --git a/tests/test_simple.py b/tests/test_simple.py
index 1ba1c5d..6bc5c87 100644
--- a/tests/test_simple.py
+++ b/tests/test_simple.py
@@ -1,4 +1,4 @@
-from nbconvert import main, converters
+from nbconvert import main, converters , NbconvertApp
 from converters.rst import ConverterRST
 import nose.tools as nt
 
@@ -26,11 +26,13 @@ class TestSimple(object):
 
     def outfile_exists(self, fmt):
         extension = converters[fmt].extension
+        print("==out to ==>>",os.path.join(self.wrkdir,
+                                           self.basename + '.' + extension))
         return os.path.exists(os.path.join(self.wrkdir,
                                            self.basename + '.' + extension))
 
     def test_simple(self):
-        c = ConverterRST(self.infile)
+        c = ConverterRST(infile=self.infile)
         f = c.render()
         nt.assert_true(f.endswith('.rst'), 'changed file extension to rst')
 
@@ -39,7 +41,13 @@ class TestSimple(object):
         Run the 'main' method to convert the input file to the given
         format and check that the expected output file exists.
         """
-        main(self.infile, format=fmt)
+        app = NbconvertApp.instance()
+        app.initialize()
+        app.extra_args = [self.infile]
+        app.fmt = fmt
+        app.start()
+
+        app.run()
         nt.assert_true(self.outfile_exists(fmt))
 
     def test_main(self):
@@ -77,7 +85,7 @@ class TestSimple(object):
                 cell_nb.source = '\n'.join(cell_nb.source)
 
             # Render to rst
-            c = ConverterRST('')
+            c = ConverterRST()
             rst_list = c.render_heading(cell_nb)
 
             # render should return a list