import unittest


class TestExtensions(unittest.TestCase):
    def test_import_extension(self):
        import pybel.ext.test

        assert pybel.ext.test.an_extension_function() == 42

    def test_import_extension_2(self):
        from pybel.ext.test import an_extension_function

        assert an_extension_function() == 42

    def test_import_extension_3(self):
        from pybel.ext import test

        assert test.an_extension_function() == 42

import unittest


class TestExtensions(unittest.TestCase):
    def test_import_extension(self):
        import pybel.ext.test

        assert pybel.ext.test.an_extension_function() == 42

    def test_import_extension_2(self):
        from pybel.ext.test import an_extension_function

        assert an_extension_function() == 42

    def test_import_extension_3(self):
        from pybel.ext import test

        assert test.an_extension_function() == 42

    def test_import_extension_4(self):
        with self.assertRaises(ImportError):
            from pybel.ext import not_an_extension

Add a test for importing a nonexistent extension
Add a test for importing a nonexistent extension

  import unittest
  
  
  class TestExtensions(unittest.TestCase):
      def test_import_extension(self):
          import pybel.ext.test
  
          assert pybel.ext.test.an_extension_function() == 42
  
      def test_import_extension_2(self):
          from pybel.ext.test import an_extension_function
  
          assert an_extension_function() == 42
  
      def test_import_extension_3(self):
          from pybel.ext import test
  
          assert test.an_extension_function() == 42
  
+     def test_import_extension_4(self):
+         with self.assertRaises(ImportError):
+             from pybel.ext import not_an_extension
+ 
Add a test for importing a nonexistent extension
## Code Before:
import unittest


class TestExtensions(unittest.TestCase):
    def test_import_extension(self):
        import pybel.ext.test

        assert pybel.ext.test.an_extension_function() == 42

    def test_import_extension_2(self):
        from pybel.ext.test import an_extension_function

        assert an_extension_function() == 42

    def test_import_extension_3(self):
        from pybel.ext import test

        assert test.an_extension_function() == 42

## Instruction:
Add a test for importing a nonexistent extension
## Code After:
import unittest


class TestExtensions(unittest.TestCase):
    def test_import_extension(self):
        import pybel.ext.test

        assert pybel.ext.test.an_extension_function() == 42

    def test_import_extension_2(self):
        from pybel.ext.test import an_extension_function

        assert an_extension_function() == 42

    def test_import_extension_3(self):
        from pybel.ext import test

        assert test.an_extension_function() == 42

    def test_import_extension_4(self):
        with self.assertRaises(ImportError):
            from pybel.ext import not_an_extension
