Add tests and doc for Brandon's -m flag.

1 files changed, 41 insertions, 27 deletions

diff --git a/coverage/execfile.py b/coverage/execfile.py
index 335bf617..a32957c1 100644
--- a/coverage/execfile.py
+++ b/coverage/execfile.py
@@ -17,35 +17,48 @@ except KeyError:
 def run_python_module(modulename, args):
     """Run a python module, as though with ``python -m name args...``.
 
+    `modulename` is the name of the module, possibly a dot-separated name.
+    `args` is the argument array to present as sys.argv, including the first
+    element naming the module being executed.
+
     """
-    # Search for the module - inside its parent package, if any - using
-    # standard import mechanics.
-    if '.' in modulename:
-        packagename, name = modulename.rsplit('.')
-        package = __import__(packagename, fromlist=['__path__'])
-        searchpath = package.__path__
-    else:
-        packagename = None
-        name = modulename
-        searchpath = None  # means "top-level search" to find_module()
-    openfile, pathname, description = imp.find_module(name, searchpath)
-
-    # Complain if this is a magic non-file module.
-    if openfile is None and pathname is None:
-        raise NoSource("module does not live in a file: %r" % modulename)
-
-    # If `modulename` is actually a package, not a mere module, then we
-    # pretend to be Python 2.7 and try running its __main__.py script.
-    if openfile is None:
-        packagename = modulename
-        name = '__main__'
-
-        package = __import__(packagename, fromlist=['__path__'])
-        searchpath = package.__path__
-        openfile, pathname, description = imp.find_module(name, searchpath)
+    openfile = None
+    glo, loc = globals(), locals()
+    try:
+        try:
+            # Search for the module - inside its parent package, if any - using
+            # standard import mechanics.
+            if '.' in modulename:
+                packagename, name = modulename.rsplit('.', 1)
+                package = __import__(packagename, glo, loc, ['__path__'])
+                searchpath = package.__path__
+            else:
+                packagename, name = None, modulename
+                searchpath = None  # "top-level search" in imp.find_module()
+            openfile, pathname, _ = imp.find_module(name, searchpath)
+
+            # Complain if this is a magic non-file module.
+            if openfile is None and pathname is None:
+                raise NoSource(
+                    "module does not live in a file: %r" % modulename
+                    )
+
+            # If `modulename` is actually a package, not a mere module, then we
+            # pretend to be Python 2.7 and try running its __main__.py script.
+            if openfile is None:
+                packagename = modulename
+                name = '__main__'
+                package = __import__(packagename, glo, loc, ['__path__'])
+                searchpath = package.__path__
+                openfile, pathname, _ = imp.find_module(name, searchpath)
+        except ImportError:
+            _, err, _ = sys.exc_info()
+            raise NoSource(str(err))
+    finally:
+        if openfile:
+            openfile.close()
 
     # Finally, hand the file off to run_python_file for execution.
-    openfile.close()
     run_python_file(pathname, args, package=packagename)
 
 
@@ -54,7 +67,8 @@ def run_python_file(filename, args, package=None):
 
     `filename` is the path to the file to execute, it need not be a .py file.
     `args` is the argument array to present as sys.argv, including the first
-    element representing the file being executed.
+    element naming the file being executed.  `package` is the name of the
+    enclosing package, if any.
 
     """
     # Create a module to serve as __main__