Revised following comments from Chris Church.

Now uses sha1 checksums following merge of 9688.
Also I undid the changes I made to fetch.py
win_template.py now uses conn.shell.has_trailing_slash and
conn.shell.join_path
updated integration tests.

lib/ansible/module_utils/powershell.ps1

@@ -142,14 +142,14 @@ Function ConvertTo-Bool
     return
 }
 
-# Helper function to calculate md5 of a file in a way which powershell 3 
+# Helper function to calculate a hash of a file in a way which powershell 3 
 # and above can handle:
-Function Get-FileMd5($path)
+Function Get-FileChecksum($path)
 {
     $hash = ""
     If (Test-Path -PathType Leaf $path)
     {
-        $sp = new-object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider;
+        $sp = new-object -TypeName System.Security.Cryptography.SHA1CryptoServiceProvider;
         $fp = [System.IO.File]::Open($path, [System.IO.Filemode]::Open, [System.IO.FileAccess]::Read);
         [System.BitConverter]::ToString($sp.ComputeHash($fp)).Replace("-", "").ToLower();
         $fp.Dispose();

lib/ansible/runner/action_plugins/fetch.py

@@ -127,13 +127,13 @@ class ActionModule(object):
             elif remote_checksum == '2':
                 result = dict(msg="no read permission on remote file, not transferring, ignored", file=source, changed=False)
             elif remote_checksum == '3':
-                result = dict(failed=True, msg="remote file is a directory, fetch cannot work on directories", file=source, changed=False)
+                result = dict(msg="remote file is a directory, fetch cannot work on directories", file=source, changed=False)
             elif remote_checksum == '4':
                 result = dict(msg="python isn't present on the system.  Unable to compute checksum", file=source, changed=False)
             return ReturnData(conn=conn, result=result)
 
         # calculate checksum for the local file
-        local_checksum = utils.md5(dest)
+        local_checksum = utils.checksum(dest)
 
         if remote_checksum != local_checksum:
             # create the containing directories, if needed
@@ -147,8 +147,7 @@ class ActionModule(object):
                 f = open(dest, 'w')
                 f.write(remote_data)
                 f.close()
-            new_checksum = utils.md5(dest)
+            new_checksum = utils.secure_hash(dest)
-            # new_checksum = utils.secure_hash(dest)
             # For backwards compatibility.  We'll return None on FIPS enabled
             # systems
             try:

lib/ansible/runner/action_plugins/win_template.py

@@ -75,10 +75,9 @@ class ActionModule(object):
             else:
                 source = utils.path_dwim(self.runner.basedir, source)
 
-
+        if conn.shell.path_has_trailing_slash(dest):
-        if dest.endswith("\\"): # TODO: Check that this fixes the path for Windows hosts.
             base = os.path.basename(source)
-            dest = os.path.join(dest, base)
+            dest = conn.shell.join_path(dest, base)
 
         # template the source data locally & get ready to transfer
         try:

test/integration/roles/test_win_copy/tasks/main.yml

@@ -62,12 +62,14 @@
 - name: verify that the file checksum is correct
   assert: 
     that: 
-      - "copy_result.checksum[0] == 'c47397529fe81ab62ba3f85e9f4c71f2'"
+      - "copy_result.checksum[0] == 'c79a6506c1c948be0d456ab5104d5e753ab2f3e6'"
 
 - name: check the stat results of the file
   win_stat: path={{output_file}}
   register: stat_results
 
+- debug: var=stat_results
+
 - name: assert the stat results are correct
   assert: 
     that:
@@ -76,7 +78,7 @@
 #      - "stat_results.stat.isfifo == false"
 #      - "stat_results.stat.isreg == true"
 #      - "stat_results.stat.issock == false"
-      - "stat_results.stat.md5[0] == 'c47397529fe81ab62ba3f85e9f4c71f2'"
+      - "stat_results.stat.checksum[0] == 'c79a6506c1c948be0d456ab5104d5e753ab2f3e6'"
 
 - name: overwrite the file via same means
   win_copy: src=foo.txt dest={{output_file}}