Fix random test failure.

The filename was generated taking the last digits of a randomly
generated number between 0 and 1, if the number is small enough, it's
repr ends with `e-5`, or less (the probability is actually close to
1/1000 because the biggest number we can get with e-5 is (1e-4 -
epsilon).

We actually did hit that on our CI:

- https://ci.appveyor.com/project/IPython/ipython/build/1.0.839/job/mk4l08s295ynkfs5

```
======================================================================
ERROR: test_run_submodule_with_absolute_import (IPython.core.tests.test_run.TestMagicRunWithPackage)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "c:\python36-x64\lib\site-packages\IPython\core\tests\test_run.py", line 455, in test_run_submodule_with_absolute_import
    self.check_run_submodule('absolute')
  File "c:\python36-x64\lib\site-packages\IPython\core\tests\test_run.py", line 450, in check_run_submodule
    self.assertEqual(_ip.user_ns['x'], self.value,
KeyError: 'x'
-------------------- >> begin captured stdout << ---------------------
  File "C:\Users\appveyor\AppData\Local\Temp\1\tmp4asmvv33\tmpqpswwe9n\tmp065832886952393e-05\absolute.py", line 2
    from tmp065832886952393e-05.sub import x
                            ^
SyntaxError: invalid syntax
```

Actually pick a random string now we should have less chance of being
invalid identifier.

IPython/core/tests/test_run.py

@@ -1,547 +1,548 b''
 # encoding: utf-8
 """Tests for code execution (%run and related), which is particularly tricky.
 
 Because of how %run manages namespaces, and the fact that we are trying here to
 verify subtle object deletion and reference counting issues, the %run tests
 will be kept in this separate file.  This makes it easier to aggregate in one
 place the tricks needed to handle it; most other magics are much easier to test
 and we do so in a common test_magic file.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 
 
 import functools
 import os
 from os.path import join as pjoin
 import random
+import string
 import sys
 import textwrap
 import unittest
 from unittest.mock import patch
 
 import nose.tools as nt
 from nose import SkipTest
 
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 from IPython.utils import py3compat
 from IPython.utils.io import capture_output
 from IPython.utils.tempdir import TemporaryDirectory
 from IPython.core import debugger
 
 
 def doctest_refbug():
     """Very nasty problem with references held by multiple runs of a script.
     See: https://github.com/ipython/ipython/issues/141
 
     In [1]: _ip.clear_main_mod_cache()
     # random
 
     In [2]: %run refbug
 
     In [3]: call_f()
     lowercased: hello
 
     In [4]: %run refbug
 
     In [5]: call_f()
     lowercased: hello
     lowercased: hello
     """
 
 
 def doctest_run_builtins():
     r"""Check that %run doesn't damage __builtins__.
 
     In [1]: import tempfile
 
     In [2]: bid1 = id(__builtins__)
 
     In [3]: fname = tempfile.mkstemp('.py')[1]
 
     In [3]: f = open(fname,'w')
 
     In [4]: dummy= f.write('pass\n')
 
     In [5]: f.flush()
 
     In [6]: t1 = type(__builtins__)
 
     In [7]: %run $fname
 
     In [7]: f.close()
 
     In [8]: bid2 = id(__builtins__)
 
     In [9]: t2 = type(__builtins__)
 
     In [10]: t1 == t2
     Out[10]: True
 
     In [10]: bid1 == bid2
     Out[10]: True
 
     In [12]: try:
        ....:     os.unlink(fname)
        ....: except:
        ....:     pass
        ....:
     """
 
 
 def doctest_run_option_parser():
     r"""Test option parser in %run.
 
     In [1]: %run print_argv.py
     []
 
     In [2]: %run print_argv.py print*.py
     ['print_argv.py']
 
     In [3]: %run -G print_argv.py print*.py
     ['print*.py']
 
     """
 
 
 @dec.skip_win32
 def doctest_run_option_parser_for_posix():
     r"""Test option parser in %run (Linux/OSX specific).
 
     You need double quote to escape glob in POSIX systems:
 
     In [1]: %run print_argv.py print\\*.py
     ['print*.py']
 
     You can't use quote to escape glob in POSIX systems:
 
     In [2]: %run print_argv.py 'print*.py'
     ['print_argv.py']
 
     """
 
 
 @dec.skip_if_not_win32
 def doctest_run_option_parser_for_windows():
     r"""Test option parser in %run (Windows specific).
 
     In Windows, you can't escape ``*` `by backslash:
 
     In [1]: %run print_argv.py print\\*.py
     ['print\\*.py']
 
     You can use quote to escape glob:
 
     In [2]: %run print_argv.py 'print*.py'
     ['print*.py']
 
     """
 
 
 @py3compat.doctest_refactor_print
 def doctest_reset_del():
     """Test that resetting doesn't cause errors in __del__ methods.
 
     In [2]: class A(object):
        ...:     def __del__(self):
        ...:         print str("Hi")
        ...:
 
     In [3]: a = A()
 
     In [4]: get_ipython().reset()
     Hi
 
     In [5]: 1+1
     Out[5]: 2
     """
 
 # For some tests, it will be handy to organize them in a class with a common
 # setup that makes a temp file
 
 class TestMagicRunPass(tt.TempFileMixin):
 
     def setup(self):
         content = "a = [1,2,3]\nb = 1"
         self.mktmp(content)
         
     def run_tmpfile(self):
         _ip = get_ipython()
         # This fails on Windows if self.tmpfile.name has spaces or "~" in it.
         # See below and ticket https://bugs.launchpad.net/bugs/366353
         _ip.magic('run %s' % self.fname)
         
     def run_tmpfile_p(self):
         _ip = get_ipython()
         # This fails on Windows if self.tmpfile.name has spaces or "~" in it.
         # See below and ticket https://bugs.launchpad.net/bugs/366353
         _ip.magic('run -p %s' % self.fname)
 
     def test_builtins_id(self):
         """Check that %run doesn't damage __builtins__ """
         _ip = get_ipython()
         # Test that the id of __builtins__ is not modified by %run
         bid1 = id(_ip.user_ns['__builtins__'])
         self.run_tmpfile()
         bid2 = id(_ip.user_ns['__builtins__'])
         nt.assert_equal(bid1, bid2)
 
     def test_builtins_type(self):
         """Check that the type of __builtins__ doesn't change with %run.
 
         However, the above could pass if __builtins__ was already modified to
         be a dict (it should be a module) by a previous use of %run.  So we
         also check explicitly that it really is a module:
         """
         _ip = get_ipython()
         self.run_tmpfile()
         nt.assert_equal(type(_ip.user_ns['__builtins__']),type(sys))
         
     def test_run_profile( self ):
         """Test that the option -p, which invokes the profiler, do not
         crash by invoking execfile"""
         self.run_tmpfile_p()
 
     def test_run_debug_twice(self):
         # https://github.com/ipython/ipython/issues/10028
         _ip = get_ipython()
         with tt.fake_input(['c']):
             _ip.magic('run -d %s' % self.fname)
         with tt.fake_input(['c']):
             _ip.magic('run -d %s' % self.fname)
 
     def test_run_debug_twice_with_breakpoint(self):
         """Make a valid python temp file."""
         _ip = get_ipython()
         with tt.fake_input(['b 2', 'c', 'c']):
             _ip.magic('run -d %s' % self.fname)
 
         with tt.fake_input(['c']):
             with tt.AssertNotPrints('KeyError'):
                 _ip.magic('run -d %s' % self.fname)
 
 
 class TestMagicRunSimple(tt.TempFileMixin):
 
     def test_simpledef(self):
         """Test that simple class definitions work."""
         src = ("class foo: pass\n"
                "def f(): return foo()")
         self.mktmp(src)
         _ip.magic('run %s' % self.fname)
         _ip.run_cell('t = isinstance(f(), foo)')
         nt.assert_true(_ip.user_ns['t'])
 
     def test_obj_del(self):
         """Test that object's __del__ methods are called on exit."""
         if sys.platform == 'win32':
             try:
                 import win32api
             except ImportError:
                 raise SkipTest("Test requires pywin32")
         src = ("class A(object):\n"
                "    def __del__(self):\n"
                "        print 'object A deleted'\n"
                "a = A()\n")
         self.mktmp(py3compat.doctest_refactor_print(src))
         if dec.module_not_available('sqlite3'):
             err = 'WARNING: IPython History requires SQLite, your history will not be saved\n'
         else:
             err = None
         tt.ipexec_validate(self.fname, 'object A deleted', err)
     
     def test_aggressive_namespace_cleanup(self):
         """Test that namespace cleanup is not too aggressive GH-238
 
         Returning from another run magic deletes the namespace"""
         # see ticket https://github.com/ipython/ipython/issues/238
         
         with tt.TempFileMixin() as empty:
             empty.mktmp('')
             # On Windows, the filename will have \users in it, so we need to use the
             # repr so that the \u becomes \\u.
             src = ("ip = get_ipython()\n"
                    "for i in range(5):\n"
                    "   try:\n"
                    "       ip.magic(%r)\n"
                    "   except NameError as e:\n"
                    "       print(i)\n"
                    "       break\n" % ('run ' + empty.fname))
             self.mktmp(src)
             _ip.magic('run %s' % self.fname)
             _ip.run_cell('ip == get_ipython()')
             nt.assert_equal(_ip.user_ns['i'], 4)
     
     def test_run_second(self):
         """Test that running a second file doesn't clobber the first, gh-3547
         """
         self.mktmp("avar = 1\n"
                    "def afunc():\n"
                    "  return avar\n")
 
         with tt.TempFileMixin() as empty:
             empty.mktmp("")
             
             _ip.magic('run %s' % self.fname)
             _ip.magic('run %s' % empty.fname)
             nt.assert_equal(_ip.user_ns['afunc'](), 1)
 
     @dec.skip_win32
     def test_tclass(self):
         mydir = os.path.dirname(__file__)
         tc = os.path.join(mydir, 'tclass')
         src = ("%%run '%s' C-first\n"
                "%%run '%s' C-second\n"
                "%%run '%s' C-third\n") % (tc, tc, tc)
         self.mktmp(src, '.ipy')
         out = """\
 ARGV 1-: ['C-first']
 ARGV 1-: ['C-second']
 tclass.py: deleting object: C-first
 ARGV 1-: ['C-third']
 tclass.py: deleting object: C-second
 tclass.py: deleting object: C-third
 """
         if dec.module_not_available('sqlite3'):
             err = 'WARNING: IPython History requires SQLite, your history will not be saved\n'
         else:
             err = None
         tt.ipexec_validate(self.fname, out, err)
 
     def test_run_i_after_reset(self):
         """Check that %run -i still works after %reset (gh-693)"""
         src = "yy = zz\n"
         self.mktmp(src)
         _ip.run_cell("zz = 23")
         _ip.magic('run -i %s' % self.fname)
         nt.assert_equal(_ip.user_ns['yy'], 23)
         _ip.magic('reset -f')
         _ip.run_cell("zz = 23")
         _ip.magic('run -i %s' % self.fname)
         nt.assert_equal(_ip.user_ns['yy'], 23)
     
     def test_unicode(self):
         """Check that files in odd encodings are accepted."""
         mydir = os.path.dirname(__file__)
         na = os.path.join(mydir, 'nonascii.py')
         _ip.magic('run "%s"' % na)
         nt.assert_equal(_ip.user_ns['u'], u'Ўт№Ф')
 
     def test_run_py_file_attribute(self):
         """Test handling of `__file__` attribute in `%run <file>.py`."""
         src = "t = __file__\n"
         self.mktmp(src)
         _missing = object()
         file1 = _ip.user_ns.get('__file__', _missing)
         _ip.magic('run %s' % self.fname)
         file2 = _ip.user_ns.get('__file__', _missing)
 
         # Check that __file__ was equal to the filename in the script's
         # namespace.
         nt.assert_equal(_ip.user_ns['t'], self.fname)
 
         # Check that __file__ was not leaked back into user_ns.
         nt.assert_equal(file1, file2)
 
     def test_run_ipy_file_attribute(self):
         """Test handling of `__file__` attribute in `%run <file.ipy>`."""
         src = "t = __file__\n"
         self.mktmp(src, ext='.ipy')
         _missing = object()
         file1 = _ip.user_ns.get('__file__', _missing)
         _ip.magic('run %s' % self.fname)
         file2 = _ip.user_ns.get('__file__', _missing)
 
         # Check that __file__ was equal to the filename in the script's
         # namespace.
         nt.assert_equal(_ip.user_ns['t'], self.fname)
 
         # Check that __file__ was not leaked back into user_ns.
         nt.assert_equal(file1, file2)
 
     def test_run_formatting(self):
         """ Test that %run -t -N<N> does not raise a TypeError for N > 1."""
         src = "pass"
         self.mktmp(src)
         _ip.magic('run -t -N 1 %s' % self.fname)
         _ip.magic('run -t -N 10 %s' % self.fname)
     
     def test_ignore_sys_exit(self):
         """Test the -e option to ignore sys.exit()"""
         src = "import sys; sys.exit(1)"
         self.mktmp(src)
         with tt.AssertPrints('SystemExit'):
             _ip.magic('run %s' % self.fname)
         
         with tt.AssertNotPrints('SystemExit'):
             _ip.magic('run -e %s' % self.fname)
 
     def test_run_nb(self):
         """Test %run notebook.ipynb"""
         from nbformat import v4, writes
         nb = v4.new_notebook(
            cells=[
                 v4.new_markdown_cell("The Ultimate Question of Everything"),
                 v4.new_code_cell("answer=42")
             ]
         )
         src = writes(nb, version=4)
         self.mktmp(src, ext='.ipynb')
         
         _ip.magic("run %s" % self.fname)
         
         nt.assert_equal(_ip.user_ns['answer'], 42)
 
     def test_file_options(self):
         src = ('import sys\n'
                'a = " ".join(sys.argv[1:])\n')
         self.mktmp(src)
         test_opts = '-x 3 --verbose'
         _ip.run_line_magic("run", '{0} {1}'.format(self.fname, test_opts))
         nt.assert_equal(_ip.user_ns['a'], test_opts)
 
 
 class TestMagicRunWithPackage(unittest.TestCase):
 
     def writefile(self, name, content):
         path = os.path.join(self.tempdir.name, name)
         d = os.path.dirname(path)
         if not os.path.isdir(d):
             os.makedirs(d)
         with open(path, 'w') as f:
             f.write(textwrap.dedent(content))
 
     def setUp(self):
-        self.package = package = 'tmp{0}'.format(repr(random.random())[2:])
-        """Temporary valid python package name."""
+        self.package = package = 'tmp{0}'.format(''.join([random.choice(string.ascii_letters) for i in range(10)]))
+        """Temporary  (probably) valid python package name."""
 
         self.value = int(random.random() * 10000)
 
         self.tempdir = TemporaryDirectory()
         self.__orig_cwd = os.getcwd()
         sys.path.insert(0, self.tempdir.name)
 
         self.writefile(os.path.join(package, '__init__.py'), '')
         self.writefile(os.path.join(package, 'sub.py'), """
         x = {0!r}
         """.format(self.value))
         self.writefile(os.path.join(package, 'relative.py'), """
         from .sub import x
         """)
         self.writefile(os.path.join(package, 'absolute.py'), """
         from {0}.sub import x
         """.format(package))
         self.writefile(os.path.join(package, 'args.py'), """
         import sys
         a = " ".join(sys.argv[1:])
         """.format(package))
 
     def tearDown(self):
         os.chdir(self.__orig_cwd)
         sys.path[:] = [p for p in sys.path if p != self.tempdir.name]
         self.tempdir.cleanup()
 
     def check_run_submodule(self, submodule, opts=''):
         _ip.user_ns.pop('x', None)
         _ip.magic('run {2} -m {0}.{1}'.format(self.package, submodule, opts))
         self.assertEqual(_ip.user_ns['x'], self.value,
                          'Variable `x` is not loaded from module `{0}`.'
                          .format(submodule))
 
     def test_run_submodule_with_absolute_import(self):
         self.check_run_submodule('absolute')
 
     def test_run_submodule_with_relative_import(self):
         """Run submodule that has a relative import statement (#2727)."""
         self.check_run_submodule('relative')
 
     def test_prun_submodule_with_absolute_import(self):
         self.check_run_submodule('absolute', '-p')
 
     def test_prun_submodule_with_relative_import(self):
         self.check_run_submodule('relative', '-p')
 
     def with_fake_debugger(func):
         @functools.wraps(func)
         def wrapper(*args, **kwds):
             with patch.object(debugger.Pdb, 'run', staticmethod(eval)):
                 return func(*args, **kwds)
         return wrapper
 
     @with_fake_debugger
     def test_debug_run_submodule_with_absolute_import(self):
         self.check_run_submodule('absolute', '-d')
 
     @with_fake_debugger
     def test_debug_run_submodule_with_relative_import(self):
         self.check_run_submodule('relative', '-d')
 
     def test_module_options(self):
         _ip.user_ns.pop('a', None)
         test_opts = '-x abc -m test'
         _ip.run_line_magic('run', '-m {0}.args {1}'.format(self.package, test_opts))
         nt.assert_equal(_ip.user_ns['a'], test_opts)
 
     def test_module_options_with_separator(self):
         _ip.user_ns.pop('a', None)
         test_opts = '-x abc -m test'
         _ip.run_line_magic('run', '-m {0}.args -- {1}'.format(self.package, test_opts))
         nt.assert_equal(_ip.user_ns['a'], test_opts)
 
 def test_run__name__():
     with TemporaryDirectory() as td:
         path = pjoin(td, 'foo.py')
         with open(path, 'w') as f:
             f.write("q = __name__")
         
         _ip.user_ns.pop('q', None)
         _ip.magic('run {}'.format(path))
         nt.assert_equal(_ip.user_ns.pop('q'), '__main__')
         
         _ip.magic('run -n {}'.format(path))
         nt.assert_equal(_ip.user_ns.pop('q'), 'foo')
 
         _ip.magic('run -i -n {}'.format(path))
         nt.assert_equal(_ip.user_ns.pop('q'), 'foo')
 
 
 def test_run_tb():
     """Test traceback offset in %run"""
     with TemporaryDirectory() as td:
         path = pjoin(td, 'foo.py')
         with open(path, 'w') as f:
             f.write('\n'.join([
                 "def foo():",
                 "    return bar()",
                 "def bar():",
                 "    raise RuntimeError('hello!')",
                 "foo()",
             ]))
         with capture_output() as io:
             _ip.magic('run {}'.format(path))
         out = io.stdout
         nt.assert_not_in("execfile", out)
         nt.assert_in("RuntimeError", out)
         nt.assert_equal(out.count("---->"), 3)
 
 @dec.knownfailureif(sys.platform == 'win32', "writes to io.stdout aren't captured on Windows")
 def test_script_tb():
     """Test traceback offset in `ipython script.py`"""
     with TemporaryDirectory() as td:
         path = pjoin(td, 'foo.py')
         with open(path, 'w') as f:
             f.write('\n'.join([
                 "def foo():",
                 "    return bar()",
                 "def bar():",
                 "    raise RuntimeError('hello!')",
                 "foo()",
             ]))
         out, err = tt.ipexec(path)
         nt.assert_not_in("execfile", out)
         nt.assert_in("RuntimeError", out)
         nt.assert_equal(out.count("---->"), 3)