Add a test to catch when the path is empty

IPython/nbconvert/preprocessors/tests/test_execute.py

@@ -1,107 +1,124 b''
 """
 Module with tests for the execute preprocessor.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import copy
 import glob
 import io
 import os
 import re
 
 from IPython import nbformat
 
 from .base import PreprocessorTestsBase
 from ..execute import ExecutePreprocessor
 
 from IPython.nbconvert.filters import strip_ansi
 
 addr_pat = re.compile(r'0x[0-9a-f]{7,9}')
 
 class TestExecute(PreprocessorTestsBase):
     """Contains test functions for execute.py"""
 
     @staticmethod
     def normalize_output(output):
         """
         Normalizes outputs for comparison.
         """
         output = dict(output)
         if 'metadata' in output:
             del output['metadata']
         if 'text' in output:
             output['text'] = re.sub(addr_pat, '<HEXADDR>', output['text'])
         if 'text/plain' in output.get('data', {}):
             output['data']['text/plain'] = \
                 re.sub(addr_pat, '<HEXADDR>', output['data']['text/plain'])
         if 'traceback' in output:
             tb = []
             for line in output['traceback']:
                 tb.append(strip_ansi(line))
             output['traceback'] = tb
             
         return output
 
 
     def assert_notebooks_equal(self, expected, actual):
         expected_cells = expected['cells']
         actual_cells = actual['cells']
         self.assertEqual(len(expected_cells), len(actual_cells))
 
         for expected_cell, actual_cell in zip(expected_cells, actual_cells):
             expected_outputs = expected_cell.get('outputs', [])
             actual_outputs = actual_cell.get('outputs', [])
             normalized_expected_outputs = list(map(self.normalize_output, expected_outputs))
             normalized_actual_outputs = list(map(self.normalize_output, actual_outputs))
             self.assertEqual(normalized_expected_outputs, normalized_actual_outputs)
 
             expected_execution_count = expected_cell.get('execution_count', None)
             actual_execution_count = actual_cell.get('execution_count', None)
             self.assertEqual(expected_execution_count, actual_execution_count)
 
 
     def build_preprocessor(self):
         """Make an instance of a preprocessor"""
         preprocessor = ExecutePreprocessor()
         preprocessor.enabled = True
         return preprocessor
 
 
     def test_constructor(self):
         """Can a ExecutePreprocessor be constructed?"""
         self.build_preprocessor()
 
 
     def test_run_notebooks(self):
         """Runs a series of test notebooks and compares them to their actual output"""
         current_dir = os.path.dirname(__file__)
         input_files = glob.glob(os.path.join(current_dir, 'files', '*.ipynb'))
         for filename in input_files:
             with io.open(filename) as f:
                 input_nb = nbformat.read(f, 4)
             res = self.build_resources()
             res['metadata']['path'] = os.path.dirname(filename)
             preprocessor = self.build_preprocessor()
             cleaned_input_nb = copy.deepcopy(input_nb)
             for cell in cleaned_input_nb.cells:
                 if 'execution_count' in cell:
                     del cell['execution_count']
                 cell['outputs'] = []
             output_nb, _ = preprocessor(cleaned_input_nb, res)
 
             if os.path.basename(filename) == "Disable Stdin.ipynb":
                 # We need to special-case this particular notebook, because the
                 # traceback contains machine-specific stuff like where IPython
                 # is installed. It is sufficient here to just check that an error
                 # was thrown, and that it was a StdinNotImplementedError
                 self.assertEqual(len(output_nb['cells']), 1)
                 self.assertEqual(len(output_nb['cells'][0]['outputs']), 1)
                 output = output_nb['cells'][0]['outputs'][0]
                 self.assertEqual(output['output_type'], 'error')
                 self.assertEqual(output['ename'], 'StdinNotImplementedError')
                 self.assertEqual(output['evalue'], 'raw_input was called, but this frontend does not support input requests.')
 
             else:
                 self.assert_notebooks_equal(output_nb, input_nb)
+
+    def test_empty_path(self):
+        """Can the kernel be started when the path is empty?"""
+        current_dir = os.path.dirname(__file__)
+        filename = os.path.join(current_dir, 'files', 'HelloWorld.ipynb')
+        with io.open(filename) as f:
+            input_nb = nbformat.read(f, 4)
+        res = self.build_resources()
+        res['metadata']['path'] = ''
+        preprocessor = self.build_preprocessor()
+        cleaned_input_nb = copy.deepcopy(input_nb)
+        for cell in cleaned_input_nb.cells:
+            if 'execution_count' in cell:
+                del cell['execution_count']
+            cell['outputs'] = []
+        output_nb, _ = preprocessor(cleaned_input_nb, res)
+        self.assert_notebooks_equal(output_nb, input_nb)