diff --git a/certbot-apache/certbot_apache/assertions.py b/certbot-apache/certbot_apache/assertions.py
new file mode 100644
index 000000000..17b56073a
--- /dev/null
+++ b/certbot-apache/certbot_apache/assertions.py
@@ -0,0 +1,138 @@
+from certbot_apache import interfaces
+
+
+PASS = "CERTBOT_PASS_ASSERT"
+
+
+def assertEqual(first, second):
+    """ Equality assertion """
+
+    if isinstance(first, interfaces.CommentNode):
+        assertEqualComment(first, second)
+    elif isinstance(first, interfaces.DirectiveNode):
+        assertEqualDirective(first, second)
+    elif isinstance(first, interfaces.BlockNode):
+        assertEqualBlock(first, second)
+
+    # Skip tests if filepath includes the pass value. This is done
+    # because filepath is variable of the base ParserNode interface, and
+    # unless the implementation is actually done, we cannot assume getting
+    # correct results from boolean assertion for dirty
+    if not isPass(first.filepath, second.filepath):
+        assert first.dirty == second.dirty
+        # We might want to disable this later if testing with two separate
+        # (but identical) directory structures.
+        assert first.filepath == second.filepath
+
+def assertEqualComment(first, second):
+    """ Equality assertion for CommentNode """
+
+    assert isinstance(first, interfaces.CommentNode)
+    assert isinstance(second, interfaces.CommentNode)
+
+    if not isPass(first.comment, second.comment):
+        assert first.comment == second.comment
+
+    if not isPass(first.filepath, second.filepath):
+        assert first.filepath == second.filepath
+
+def _assertEqualDirectiveComponents(first, second):
+    """ Handles assertion for instance variables for DirectiveNode and BlockNode"""
+
+    # Enabled value cannot be asserted, because Augeas implementation
+    # is unable to figure that out.
+    # assert first.enabled == second.enabled
+    if not isPass(first.name, second.name):
+        assert first.name == second.name
+
+    if not isPass(first.filepath, second.filepath):
+        assert first.filepath == second.filepath
+
+    if not isPass(first.parameters, second.parameters):
+        assert first.parameters == second.parameters
+
+def assertEqualDirective(first, second):
+    """ Equality assertion for DirectiveNode """
+
+    assert isinstance(first, interfaces.DirectiveNode)
+    assert isinstance(second, interfaces.DirectiveNode)
+    _assertEqualDirectiveComponents(first, second)
+
+def assertEqualBlock(first, second):
+    """ Equality assertion for BlockNode """
+
+    # first was checked in the assertEqual method
+    assert isinstance(first, interfaces.BlockNode)
+    assert isinstance(second, interfaces.BlockNode)
+    _assertEqualDirectiveComponents(first, second)
+    # Children cannot be asserted, because Augeas implementation will not
+    # prepopulate the sequence of children.
+    # assert len(first.children) == len(second.children)
+
+def isPass(first, second):
+    """ Checks if either first or second holds the assertion pass value """
+
+    if isinstance(first, tuple) or isinstance(first, list):
+        if PASS in first:
+            return True
+    if isinstance(second, tuple) or isinstance(second, list):
+        if PASS in second:
+            return True
+    if PASS in [first, second]:
+        return True
+    return False
+
+def isPassNodeList(nodelist):
+    """ Checks if a ParserNode in the nodelist should pass the assertion,
+    this function is used for results of find_* methods. Unimplemented find_*
+    methods should return a sequence containing a single ParserNode instance
+    with assertion pass string."""
+
+    try:
+        node = nodelist[0]
+    except IndexError:
+        node = None
+
+    if not node:
+        # Empty result means that the method is implemented
+        return False
+
+    if isinstance(node, interfaces.BlockNode):
+        return _isPassDirective(node)
+    if isinstance(node, interfaces.DirectiveNode):
+        return _isPassDirective(node)
+    return _isPassComment(node)
+
+def _isPassDirective(block):
+    """ Checks if BlockNode or DirectiveNode should pass the assertion """
+
+    if block.name == PASS:
+        return True
+    if PASS in block.parameters:
+        return True
+    if block.filepath == PASS:
+        return True
+    return False
+
+def _isPassComment(comment):
+    """ Checks if CommentNode should pass the assertion """
+
+    if comment.comment == PASS:
+        return True
+    if comment.filepath == PASS:
+        return True
+    return False
+
+def assertSimple(first, second):
+    """ Simple assertion """
+    if not isPass(first, second):
+        assert first == second
+
+def assertSimpleList(first, second):
+    """ Simple assertion that lists contain the same objects. This needs to
+    be used when there's uncertainty about the ordering of the list. """
+
+    if not isPass(first, second):
+        if first:
+            for f in first:
+                assert f in second
diff --git a/certbot-apache/certbot_apache/augeasparser.py b/certbot-apache/certbot_apache/augeasparser.py
new file mode 100644
index 000000000..3d50001f1
--- /dev/null
+++ b/certbot-apache/certbot_apache/augeasparser.py
@@ -0,0 +1,127 @@
+""" Augeas implementation of the ParserNode interface """
+from certbot_apache import assertions
+from certbot_apache import interfaces
+from certbot_apache import parsernode_util as util
+
+
+class AugeasParserNode(interfaces.ParserNode):
+    """ Augeas implementation of ParserNode interface """
+
+    def __init__(self, **kwargs):
+        ancestor, dirty, filepath, metadata = util.parsernode_kwargs(kwargs)
+        self.ancestor = ancestor
+        # self.filepath = filepath
+        self.filepath = assertions.PASS
+        self.dirty = dirty
+        self.metadata = metadata
+
+    def save(self, msg):  # pragma: no cover
+        pass
+
+
+class AugeasCommentNode(AugeasParserNode):
+    """ Augeas implementation of CommentNode interface """
+
+    def __init__(self, **kwargs):
+        comment, kwargs = util.commentnode_kwargs(kwargs)
+        super(AugeasCommentNode, self).__init__(**kwargs)
+        self.comment = comment
+
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return (self.comment == other.comment and
+                    self.filepath == other.filepath and
+                    self.dirty == other.dirty and
+                    self.ancestor == other.ancestor and
+                    self.metadata == other.metadata)
+
+
+class AugeasDirectiveNode(AugeasParserNode):
+    """ Augeas implementation of DirectiveNode interface """
+
+    def __init__(self, **kwargs):
+        name, parameters, enabled, kwargs = util.directivenode_kwargs(kwargs)
+        super(AugeasDirectiveNode, self).__init__(**kwargs)
+        self.name = name
+        self.parameters = parameters
+        self.enabled = enabled
+
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return (self.name == other.name and
+                    self.filepath == other.filepath and
+                    self.parameters == other.parameters and
+                    self.enabled == other.enabled and
+                    self.dirty == other.dirty and
+                    self.ancestor == other.ancestor and
+                    self.metadata == other.metadata)
+
+    def set_parameters(self, parameters):
+        self.parameters = parameters
+
+
+class AugeasBlockNode(AugeasDirectiveNode):
+    """ Augeas implementation of BlockNode interface """
+
+    def __init__(self, **kwargs):
+        super(AugeasBlockNode, self).__init__(**kwargs)
+        self.children = ()
+
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return (self.name == other.name and
+                    self.filepath == other.filepath and
+                    self.parameters == other.parameters and
+                    self.children == other.children and
+                    self.enabled == other.enabled and
+                    self.dirty == other.dirty and
+                    self.ancestor == other.ancestor and
+                    self.metadata == other.metadata)
+
+
+    def add_child_block(self, name, parameters=None, position=None):
+        new_block = AugeasBlockNode(name=assertions.PASS,
+                                    ancestor=self,
+                                    filepath=assertions.PASS)
+        self.children += (new_block,)
+        return new_block
+
+    def add_child_directive(self, name, parameters=None, position=None):
+        new_dir = AugeasDirectiveNode(name=assertions.PASS,
+                                      ancestor=self,
+                                      filepath=assertions.PASS)
+        self.children += (new_dir,)
+        return new_dir
+
+    def add_child_comment(self, comment="", position=None):
+        new_comment = AugeasCommentNode(comment=assertions.PASS,
+                                        ancestor=self,
+                                        filepath=assertions.PASS)
+        self.children += (new_comment,)
+        return new_comment
+
+    def find_blocks(self, name, exclude=True):
+        return [AugeasBlockNode(name=assertions.PASS,
+                                ancestor=self,
+                                filepath=assertions.PASS)]
+
+    def find_directives(self, name, exclude=True):
+        return [AugeasDirectiveNode(name=assertions.PASS,
+                                    ancestor=self,
+                                    filepath=assertions.PASS)]
+
+    def find_comments(self, comment, exact=False):
+        return [AugeasCommentNode(comment=assertions.PASS,
+                                  ancestor=self,
+                                  filepath=assertions.PASS)]
+
+    def delete_child(self, child):  # pragma: no cover
+        pass
+
+    def unsaved_files(self):  # pragma: no cover
+        return [assertions.PASS]
+
+
+interfaces.CommentNode.register(AugeasCommentNode)
+interfaces.DirectiveNode.register(AugeasDirectiveNode)
+interfaces.BlockNode.register(AugeasBlockNode)
diff --git a/certbot-apache/certbot_apache/dualparser.py b/certbot-apache/certbot_apache/dualparser.py
new file mode 100644
index 000000000..f9186440e
--- /dev/null
+++ b/certbot-apache/certbot_apache/dualparser.py
@@ -0,0 +1,318 @@
+""" Tests for ParserNode interface """
+from certbot_apache import assertions
+from certbot_apache import augeasparser
+
+
+class DualNodeBase(object):
+    """ Dual parser interface for in development testing. This is used as the
+    base class for dual parser interface classes. This class handles runtime
+    attribute value assertions."""
+
+    def save(self, msg):  # pragma: no cover
+        """ Call save for both parsers """
+        self.primary.save(msg)
+        self.secondary.save(msg)
+
+    def __getattr__(self, aname):
+        """ Attribute value assertion """
+        firstval = getattr(self.primary, aname)
+        secondval = getattr(self.secondary, aname)
+        if not assertions.isPass(firstval, secondval):
+            assertions.assertSimple(firstval, secondval)
+        return firstval
+
+
+class DualCommentNode(DualNodeBase):
+    """ Dual parser implementation of CommentNode interface """
+
+    def __init__(self, **kwargs):
+        """ This initialization implementation allows ordinary initialization
+        of CommentNode objects as well as creating a DualCommentNode object
+        using precreated or fetched CommentNode objects if provided as optional
+        arguments primary and secondary.
+
+        Parameters other than the following are from interfaces.CommentNode:
+
+        :param CommentNode primary: Primary pre-created CommentNode, mainly
+            used when creating new DualParser nodes using add_* methods.
+        :param CommentNode secondary: Secondary pre-created CommentNode
+        """
+
+        kwargs.setdefault("primary", None)
+        kwargs.setdefault("secondary", None)
+        primary = kwargs.pop("primary")
+        secondary = kwargs.pop("secondary")
+
+        if not primary:
+            self.primary = augeasparser.AugeasCommentNode(**kwargs)
+        else:
+            self.primary = primary
+        if not secondary:
+            self.secondary = augeasparser.AugeasCommentNode(**kwargs)
+        else:
+            self.secondary = secondary
+
+        assertions.assertEqual(self.primary, self.secondary)
+
+
+class DualDirectiveNode(DualNodeBase):
+    """ Dual parser implementation of DirectiveNode interface """
+
+    def __init__(self, **kwargs):
+        """ This initialization implementation allows ordinary initialization
+        of DirectiveNode objects as well as creating a DualDirectiveNode object
+        using precreated or fetched DirectiveNode objects if provided as optional
+        arguments primary and secondary.
+
+        Parameters other than the following are from interfaces.DirectiveNode:
+
+        :param DirectiveNode primary: Primary pre-created DirectiveNode, mainly
+            used when creating new DualParser nodes using add_* methods.
+        :param DirectiveNode secondary: Secondary pre-created DirectiveNode
+
+
+        """
+
+        kwargs.setdefault("primary", None)
+        kwargs.setdefault("secondary", None)
+        primary = kwargs.pop("primary")
+        secondary = kwargs.pop("secondary")
+
+        if not primary:
+            self.primary = augeasparser.AugeasDirectiveNode(**kwargs)
+        else:
+            self.primary = primary
+
+        if not secondary:
+            self.secondary = augeasparser.AugeasDirectiveNode(**kwargs)
+        else:
+            self.secondary = secondary
+
+        assertions.assertEqual(self.primary, self.secondary)
+
+    def set_parameters(self, parameters):
+        """ Sets parameters and asserts that both implementation successfully
+        set the parameter sequence """
+
+        self.primary.set_parameters(parameters)
+        self.secondary.set_parameters(parameters)
+        assertions.assertEqual(self.primary, self.secondary)
+
+
+class DualBlockNode(DualDirectiveNode):
+    """ Dual parser implementation of BlockNode interface """
+
+    def __init__(self, **kwargs):
+        """ This initialization implementation allows ordinary initialization
+        of BlockNode objects as well as creating a DualBlockNode object
+        using precreated or fetched BlockNode objects if provided as optional
+        arguments primary and secondary.
+
+        Parameters other than the following are from interfaces.BlockNode:
+
+        :param BlockNode primary: Primary pre-created BlockNode, mainly
+            used when creating new DualParser nodes using add_* methods.
+        :param BlockNode secondary: Secondary pre-created BlockNode
+        """
+
+        kwargs.setdefault("primary", None)
+        kwargs.setdefault("secondary", None)
+        primary = kwargs.pop("primary")
+        secondary = kwargs.pop("secondary")
+
+        if not primary:
+            self.primary = augeasparser.AugeasBlockNode(**kwargs)
+        else:
+            self.primary = primary
+
+        if not secondary:
+            self.secondary = augeasparser.AugeasBlockNode(**kwargs)
+        else:
+            self.secondary = secondary
+
+        assertions.assertEqual(self.primary, self.secondary)
+
+    def add_child_block(self, name, parameters=None, position=None):
+        """ Creates a new child BlockNode, asserts that both implementations
+        did it in a similar way, and returns a newly created DualBlockNode object
+        encapsulating both of the newly created objects """
+
+        primary_new = self.primary.add_child_block(name, parameters, position)
+        secondary_new = self.secondary.add_child_block(name, parameters, position)
+        assertions.assertEqual(primary_new, secondary_new)
+        new_block = DualBlockNode(primary=primary_new, secondary=secondary_new)
+        return new_block
+
+    def add_child_directive(self, name, parameters=None, position=None):
+        """ Creates a new child DirectiveNode, asserts that both implementations
+        did it in a similar way, and returns a newly created DualDirectiveNode
+        object encapsulating both of the newly created objects """
+
+        primary_new = self.primary.add_child_directive(name, parameters, position)
+        secondary_new = self.secondary.add_child_directive(name, parameters, position)
+        assertions.assertEqual(primary_new, secondary_new)
+        new_dir = DualDirectiveNode(primary=primary_new, secondary=secondary_new)
+        return new_dir
+
+    def add_child_comment(self, comment="", position=None):
+        """ Creates a new child CommentNode, asserts that both implementations
+        did it in a similar way, and returns a newly created DualCommentNode
+        object encapsulating both of the newly created objects """
+
+        primary_new = self.primary.add_child_comment(comment, position)
+        secondary_new = self.secondary.add_child_comment(comment, position)
+        assertions.assertEqual(primary_new, secondary_new)
+        new_comment = DualCommentNode(primary=primary_new, secondary=secondary_new)
+        return new_comment
+
+    def _create_matching_list(self, primary_list, secondary_list):  # pragma: no cover
+        """ Matches the list of primary_list to a list of secondary_list and
+        returns a list of tuples. This is used to create results for find_
+        methods. """
+
+        matched = list()
+        for p in primary_list:
+            match = None
+            for s in secondary_list:
+                try:
+                    assertions.assertEqual(p, s)
+                    match = s
+                except AssertionError:
+                    continue
+            if match:
+                matched.append((p,s))
+            else:
+                raise AssertionError("Could not find a matching node.")
+        return matched
+
+    def find_blocks(self, name, exclude=True):  # pragma: no cover
+        """
+        Performs a search for BlockNodes using both implementations and does simple
+        checks for results. This is built upon the assumption that unimplemented
+        find_* methods return a list with a single assertion passing object.
+        After the assertion, it creates a list of newly created DualBlockNode
+        instances that encapsulate the pairs of returned BlockNode objects.
+        """
+
+        primary_blocks = self.primary.find_blocks(name, exclude)
+        secondary_blocks = self.secondary.find_blocks(name, exclude)
+
+        # The order of search results for Augeas implementation cannot be
+        # assured.
+
+        pass_primary = assertions.isPassNodeList(primary_blocks)
+        pass_secondary = assertions.isPassNodeList(secondary_blocks)
+        new_blocks = list()
+
+        if pass_primary and pass_secondary:
+            # Both unimplemented
+            new_blocks.append(DualBlockNode(primary=primary_blocks[0],
+                                            secondary=secondary_blocks[0]))
+        elif pass_primary:
+            for c in secondary_blocks:
+                new_blocks.append(DualBlockNode(primary=primary_blocks[0],
+                                                secondary=c))
+        elif pass_secondary:
+            for c in primary_blocks:
+                new_blocks.append(DualBlockNode(primary=c,
+                                                secondary=secondary_blocks[0]))
+        else:
+            assert len(primary_blocks) == len(secondary_blocks)
+            matches = self._create_matching_list(primary_blocks, secondary_blocks)
+            for p,s in matches:
+                new_blocks.append(DualBlockNode(primary=p, secondary=s))
+
+        return new_blocks
+
+    def find_directives(self, name, exclude=True):  # pragma: no cover
+        """
+        Performs a search for DirectiveNodes using both implementations and
+        checks the results. This is built upon the assumption that unimplemented
+        find_* methods return a list with a single assertion passing object.
+        After the assertion, it creates a list of newly created DualDirectiveNode
+        instances that encapsulate the pairs of returned DirectiveNode objects.
+        """
+        primary_dirs = self.primary.find_directives(name, exclude)
+        secondary_dirs = self.secondary.find_directives(name, exclude)
+
+        # The order of search results for Augeas implementation cannot be
+        # assured.
+
+        pass_primary = assertions.isPassNodeList(primary_dirs)
+        pass_secondary = assertions.isPassNodeList(secondary_dirs)
+        new_dirs = list()
+
+        if pass_primary and pass_secondary:
+            # Both unimplemented
+            new_dirs.append(DualDirectiveNode(primary=primary_dirs[0],
+                                              secondary=secondary_dirs[0]))
+        elif pass_primary:
+            for c in secondary_dirs:
+                new_dirs.append(DualDirectiveNode(primary=primary_dirs[0],
+                                                  secondary=c))
+        elif pass_secondary:
+            for c in primary_dirs:
+                new_dirs.append(DualDirectiveNode(primary=c,
+                                                  secondary=secondary_dirs[0]))
+        else:
+            assert len(primary_dirs) == len(secondary_dirs)
+            matches = self._create_matching_list(primary_dirs, secondary_dirs)
+            for p,s in matches:
+                new_dirs.append(DualDirectiveNode(primary=p, secondary=s))
+
+        return new_dirs
+
+    def find_comments(self, comment, exact=False):  # pragma: no cover
+        """
+        Performs a search for CommentNodes using both implementations and
+        checks the results. This is built upon the assumption that unimplemented
+        find_* methods return a list with a single assertion passing object.
+        After the assertion, it creates a list of newly created DualCommentNode
+        instances that encapsulate the pairs of returned CommentNode objects.
+        """
+        primary_com = self.primary.find_comments(comment, exact)
+        secondary_com = self.secondary.find_comments(comment, exact)
+
+        # The order of search results for Augeas implementation cannot be
+        # assured.
+
+        pass_primary = assertions.isPassNodeList(primary_com)
+        pass_secondary = assertions.isPassNodeList(secondary_com)
+        new_com = list()
+
+        if pass_primary and pass_secondary:
+            # Both unimplemented
+            new_com.append(DualCommentNode(primary=primary_com[0],
+                                           secondary=secondary_com[0]))
+        elif pass_primary:
+            for c in secondary_com:
+                new_com.append(DualCommentNode(primary=primary_com[0],
+                                               secondary=c))
+        elif pass_secondary:
+            for c in primary_com:
+                new_com.append(DualCommentNode(primary=c,
+                                               secondary=secondary_com[0]))
+        else:
+            assert len(primary_com) == len(secondary_com)
+            matches = self._create_matching_list(primary_com, secondary_com)
+            for p,s in matches:
+                new_com.append(DualCommentNode(primary=p, secondary=s))
+
+        return new_com
+
+    def delete_child(self, child):  # pragma: no cover
+        """Deletes a child from the ParserNode implementations. The actual
+        ParserNode implementations are used here directly in order to be able
+        to match a child to the list of children."""
+
+        self.primary.delete_child(child.primary)
+        self.secondary.delete_child(child.secondary)
+
+    def unsaved_files(self):
+        """ Fetches the list of unsaved file paths and asserts that the lists
+        match """
+        primary_files = self.primary.unsaved_files()
+        secondary_files = self.secondary.unsaved_files()
+        assertions.assertSimple(primary_files, secondary_files)
+
+        return primary_files
diff --git a/certbot-apache/certbot_apache/tests/dualnode_test.py b/certbot-apache/certbot_apache/tests/dualnode_test.py
new file mode 100644
index 000000000..dc55aadcc
--- /dev/null
+++ b/certbot-apache/certbot_apache/tests/dualnode_test.py
@@ -0,0 +1,167 @@
+"""Tests for DualParserNode implementation"""
+import unittest
+
+import mock
+
+from certbot_apache import assertions
+from certbot_apache import dualparser
+
+
+class DualParserNodeTest(unittest.TestCase):
+    """DualParserNode tests"""
+    def setUp(self):  # pylint: disable=arguments-differ
+        self.block = dualparser.DualBlockNode(name="block",
+                                              ancestor=None,
+                                              filepath="/tmp/something")
+        self.block_two = dualparser.DualBlockNode(name="block",
+                                                  ancestor=self.block,
+                                                  filepath="/tmp/something")
+        self.directive = dualparser.DualDirectiveNode(name="directive",
+                                                      ancestor=self.block,
+                                                      filepath="/tmp/something")
+        self.comment = dualparser.DualCommentNode(comment="comment",
+                                                  ancestor=self.block,
+                                                  filepath="/tmp/something")
+
+    def test_create_with_primary(self):
+        cnode = dualparser.DualCommentNode(comment="comment",
+                                           ancestor=self.block,
+                                           filepath="/tmp/something",
+                                           primary=self.comment.secondary)
+        dnode = dualparser.DualDirectiveNode(name="directive",
+                                             ancestor=self.block,
+                                             filepath="/tmp/something",
+                                             primary=self.directive.secondary)
+        bnode = dualparser.DualBlockNode(name="block",
+                                         ancestor=self.block,
+                                         filepath="/tmp/something",
+                                         primary=self.block.secondary)
+        self.assertTrue(cnode.primary is self.comment.secondary)
+        self.assertTrue(dnode.primary is self.directive.secondary)
+        self.assertTrue(bnode.primary is self.block.secondary)
+
+    def test_create_with_secondary(self):
+        cnode = dualparser.DualCommentNode(comment="comment",
+                                           ancestor=self.block,
+                                           filepath="/tmp/something",
+                                           secondary=self.comment.primary)
+        dnode = dualparser.DualDirectiveNode(name="directive",
+                                             ancestor=self.block,
+                                             filepath="/tmp/something",
+                                             secondary=self.directive.primary)
+        bnode = dualparser.DualBlockNode(name="block",
+                                         ancestor=self.block,
+                                         filepath="/tmp/something",
+                                         secondary=self.block.primary)
+        self.assertTrue(cnode.secondary is self.comment.primary)
+        self.assertTrue(dnode.secondary is self.directive.primary)
+        self.assertTrue(bnode.secondary is self.block.primary)
+
+    def test_set_params(self):
+        params = ("first", "second")
+        self.directive.set_parameters(params)
+        self.assertEqual(self.directive.primary.parameters, params)
+        self.assertEqual(self.directive.secondary.parameters, params)
+
+    def test_set_parameters(self):
+        pparams = mock.MagicMock()
+        sparams = mock.MagicMock()
+        pparams.parameters = ("a", "b")
+        sparams.parameters = ("a", "b")
+        self.directive.primary.set_parameters = pparams
+        self.directive.secondary.set_parameters = sparams
+        self.directive.set_parameters(("param","seq"))
+        self.assertTrue(pparams.called)
+        self.assertTrue(sparams.called)
+
+    def test_delete_child(self):
+        pdel = mock.MagicMock()
+        sdel = mock.MagicMock()
+        self.block.primary.delete_child = pdel
+        self.block.secondary.delete_child = sdel
+        self.block.delete_child(self.comment)
+        self.assertTrue(pdel.called)
+        self.assertTrue(sdel.called)
+
+    def test_unsaved_files(self):
+        puns = mock.MagicMock()
+        suns = mock.MagicMock()
+        puns.return_value = assertions.PASS
+        suns.return_value = assertions.PASS
+        self.block.primary.unsaved_files = puns
+        self.block.secondary.unsaved_files = suns
+        self.block.unsaved_files()
+        self.assertTrue(puns.called)
+        self.assertTrue(suns.called)
+
+    def test_add_child_block(self):
+        p = mock.MagicMock()
+        p.return_value = self.block
+        s = mock.MagicMock()
+        s.return_value = self.block
+        self.block.primary.add_child_block = p
+        self.block.secondary.add_child_block = s
+        self.block.add_child_block("name")
+        self.assertTrue(p.called)
+        self.assertTrue(s.called)
+
+    def test_add_child_directive(self):
+        p = mock.MagicMock()
+        p.return_value = self.directive
+        s = mock.MagicMock()
+        s.return_value = self.directive
+        self.block.primary.add_child_directive = p
+        self.block.secondary.add_child_directive = s
+        self.block.add_child_directive("name")
+        self.assertTrue(p.called)
+        self.assertTrue(s.called)
+
+    def test_add_child_comment(self):
+        p = mock.MagicMock()
+        p.return_value = self.comment
+        s = mock.MagicMock()
+        s.return_value = self.comment
+        self.block.primary.add_child_comment = p
+        self.block.secondary.add_child_comment = s
+        self.block.add_child_comment("comment")
+        self.assertTrue(p.called)
+        self.assertTrue(s.called)
+
+    def test_find_blocks(self):
+        dblks = self.block.find_blocks("block")
+        p_dblks = [d.primary for d in dblks]
+        s_dblks = [d.secondary for d in dblks]
+        p_blks = self.block.primary.find_blocks("block")
+        s_blks = self.block.secondary.find_blocks("block")
+        # Check that every block response is represented in the list of
+        # DualParserNode instances.
+        for p in p_dblks:
+            self.assertTrue(p in p_blks)
+        for s in s_dblks:
+            self.assertTrue(s in s_blks)
+
+    def test_find_directives(self):
+        ddirs = self.block.find_directives("directive")
+        p_ddirs = [d.primary for d in ddirs]
+        s_ddirs = [d.secondary for d in ddirs]
+        p_dirs = self.block.primary.find_directives("directive")
+        s_dirs = self.block.secondary.find_directives("directive")
+        # Check that every directive response is represented in the list of
+        # DualParserNode instances.
+        for p in p_ddirs:
+            self.assertTrue(p in p_dirs)
+        for s in s_ddirs:
+            self.assertTrue(s in s_dirs)
+
+    def test_find_comments(self):
+        dcoms = self.block.find_comments("comment")
+        p_dcoms = [d.primary for d in dcoms]
+        s_dcoms = [d.secondary for d in dcoms]
+        p_coms = self.block.primary.find_comments("comment")
+        s_coms = self.block.secondary.find_comments("comment")
+        # Check that every comment response is represented in the list of
+        # DualParserNode instances.
+        for p in p_dcoms:
+            self.assertTrue(p in p_coms)
+        for s in s_dcoms:
+            self.assertTrue(s in s_coms)