Added delete-password command

Details:

* Added a 'easy-vault delete-password' command that deletes the password for
  a vault file in the keyring service. Added a corresponding
  'Keyring.delete_password()' method. (issues #33 and #35)

Signed-off-by: Andreas Maier <andreas.r.maier@gmx.de>

docs/changes.rst

@@ -38,6 +38,10 @@ Released: not yet
 
 **Enhancements:**
 
+* Added a 'easy-vault delete-password' command that deletes the password for
+  a vault file in the keyring service. Added a corresponding
+  'Keyring.delete_password()' method. (issues #33 and #35)
+
 **Cleanup:**
 
 **Known issues:**

easy_vault/_keyring.py

@@ -128,6 +128,43 @@ def set_password(self, filepath, password):
         keyring.set_password(
             self.keyring_service(), self.keyring_username(filepath), password)
 
+    def delete_password(self, filepath):
+        """
+        Delete the password for a vault file in the keyring service.
+
+        Parameters:
+
+          filepath (:term:`unicode string`):
+            Path name of the vault file. It will be normalized to identify the
+            keyring item for the vault file.
+
+        Returns:
+          bool: Indicates whether the password existed.
+
+        Raises:
+          :exc:`KeyringNotAvailable`: No keyring service available.
+          :exc:`KeyringError`: An error happend in the keyring service.
+        """
+        service = self.keyring_service()
+        username = self.keyring_username(filepath)
+        try:
+            pw = keyring.get_password(service, username)
+        except NO_KEYRING_EXCEPTION as exc:
+            raise KeyringNotAvailable(str(exc))
+        except keyring.errors.KeyringError as exc:
+            raise KeyringError(str(exc))
+
+        if pw is None:
+            return False
+
+        try:
+            keyring.delete_password(service, username)
+        except NO_KEYRING_EXCEPTION as exc:
+            raise KeyringNotAvailable(str(exc))
+        except keyring.errors.KeyringError as exc:
+            raise KeyringError(str(exc))
+        return True
+
     def is_available(self):
         """
         Indicate whether the keyring service is available on the local system.

easy_vault/cli/cli.py

@@ -23,7 +23,7 @@
 
 from ._common_options import add_options, help_option, quiet_option
 from .._version import __version__ as cli_version
-from .._keyring import Keyring, KeyringNotAvailable
+from .._keyring import Keyring, KeyringNotAvailable, KeyringException
 from .._easy_vault import EasyVault, EasyVaultException
 from .._password import get_password, set_password
 
@@ -203,6 +203,28 @@ def cli_check_keyring(**options):
         click.echo("Success! Keyring service is available")
 
 
+@cli.command('delete-password')
+@click.argument('vaultfile', type=str, metavar='VAULTFILE', required=True)
+@add_options(quiet_option)
+@add_options(help_option)
+def cli_delete_password(vaultfile, **options):
+    """
+    Delete the password for a vault file in the keyring service.
+    """
+    verbose = not options['quiet']
+
+    kr = Keyring()
+    try:
+        existed = kr.delete_password(vaultfile)
+    except KeyringException as exc:
+        raise click.ClickException(exc)
+    if verbose:
+        if existed:
+            click.echo("Success! Password in keyring service has been deleted")
+        else:
+            click.echo("Success! Password in keyring service does not exist")
+
+
 def check_exists(vaultfile):
     if not os.path.exists(vaultfile):
         raise click.ClickException(

tests/unittest/test_keyring.py

@@ -27,9 +27,10 @@
 @pytest.mark.skipif(
     not is_keyring_available(), reason="No keyring service available")
 # pylint: disable=redefined-outer-name
-def test_keyring_get_set(keyring_filepath):
+def test_keyring_get_set_delete(keyring_filepath):
     """
-    Test function for Keyring.get_password() / set_password()
+    Test function for Keyring.get_password() / set_password() /
+    delete_password()
     """
     kr = Keyring()
     password = 'mypassword'
@@ -38,13 +39,25 @@ def test_keyring_get_set(keyring_filepath):
     act_password = kr.get_password(keyring_filepath)
     assert act_password is None
 
+    # Test that the password does not exist
+    existed = kr.delete_password(keyring_filepath)
+    assert existed is False
+
     # Test that setting a password succeeds
     kr.set_password(keyring_filepath, password)
 
     # Test that getting a password succeeds and is as expected
     act_password = kr.get_password(keyring_filepath)
     assert act_password == password
 
+    # Delete the password
+    existed = kr.delete_password(keyring_filepath)
+    assert existed is True
+
+    # Test that the password does not exist
+    existed = kr.delete_password(keyring_filepath)
+    assert existed is False
+
 
 def test_keyring_available():
     """