_yaml: Remove 'node_get' and migrate all remaining calls to new API

19 files changed, 67 insertions, 167 deletions

diff --git a/src/buildstream/_context.py b/src/buildstream/_context.py
index a69d521ca..c0f50901b 100644
--- a/src/buildstream/_context.py
+++ b/src/buildstream/_context.py
@@ -387,14 +387,13 @@ class Context():
     # get_overrides():
     #
     # Fetch the override dictionary for the active project. This returns
-    # a node loaded from YAML and as such, values loaded from the returned
-    # node should be loaded using the _yaml.node_get() family of functions.
+    # a node loaded from YAML.
     #
     # Args:
     #    project_name (str): The project name
     #
     # Returns:
-    #    (dict): The overrides dictionary for the specified project
+    #    (MappingNode): The overrides dictionary for the specified project
     #
     def get_overrides(self, project_name):
         return self._project_overrides.get_mapping(project_name, default={})
@@ -478,7 +477,7 @@ class Context():
 
 # _node_get_option_str()
 #
-# Like _yaml.node_get(), but also checks value is one of the allowed option
+# Like Node.get_scalar().as_str(), but also checks value is one of the allowed option
 # strings. Fetches a value from a dictionary node, and makes sure it's one of
 # the pre-defined options.
 #
diff --git a/src/buildstream/_loader/loader.py b/src/buildstream/_loader/loader.py
index 64e7fafd0..33a7762d1 100644
--- a/src/buildstream/_loader/loader.py
+++ b/src/buildstream/_loader/loader.py
@@ -469,8 +469,6 @@ class Loader():
         sources = node.get_sequence(Symbol.SOURCES, default=[])
         element_kind = node.get_str(Symbol.KIND)
 
-        # Safe loop calling into _yaml.node_get() for each element ensures
-        # we have good error reporting
         for index, source in enumerate(sources):
             kind = source.get_str(Symbol.KIND)
             _yaml.node_del(source, Symbol.KIND)
diff --git a/src/buildstream/_projectrefs.py b/src/buildstream/_projectrefs.py
index f296858cf..e72d4757e 100644
--- a/src/buildstream/_projectrefs.py
+++ b/src/buildstream/_projectrefs.py
@@ -150,6 +150,6 @@ class ProjectRefs():
             # Pad the list with empty newly created dictionaries
             _yaml.node_extend_list(project_node, element, source_index + 1, {})
 
-            node = _yaml.node_get(project_node, dict, element, indices=[source_index])
+            node = project_node.get_sequence(element).mapping_at(source_index)
 
         return node
diff --git a/src/buildstream/_yaml.pxd b/src/buildstream/_yaml.pxd
index 91fc1180d..3fffda426 100644
--- a/src/buildstream/_yaml.pxd
+++ b/src/buildstream/_yaml.pxd
@@ -62,7 +62,6 @@ cdef class ProvenanceInformation:
 
 
 cpdef void node_del(Node node, str key, bint safe=*) except *
-cpdef object node_get(Node node, object expected_type, str key, list indices=*, object default_value=*, bint allow_none=*)
 cpdef void node_validate(Node node, list valid_keys) except *
 cpdef void node_set(Node node, object key, object value, list indices=*) except *
 cpdef list node_keys(Node node)
diff --git a/src/buildstream/_yaml.pyx b/src/buildstream/_yaml.pyx
index a2327dbc5..e69ff8ee9 100644
--- a/src/buildstream/_yaml.pyx
+++ b/src/buildstream/_yaml.pyx
@@ -206,7 +206,7 @@ cdef class SequenceNode(Node):
 
         if type(value) is not MappingNode:
             provenance = node_get_provenance(self)
-            path = ["[{}]".format(p) for p in node_find_target(provenance, self)] + ["[{}]".format(index)]
+            path = ["[{}]".format(p) for p in node_find_target(provenance.toplevel, self)] + ["[{}]".format(index)]
             raise LoadError(LoadErrorReason.INVALID_DATA,
                             "{}: Value of '{}' is not of the expected type '{}'"
                             .format(provenance, path, MappingNode.__name__))
@@ -217,7 +217,7 @@ cdef class SequenceNode(Node):
 
         if type(value) is not SequenceNode:
             provenance = node_get_provenance(self)
-            path = ["[{}]".format(p) for p in node_find_target(provenance, self)] + ["[{}]".format(index)]
+            path = ["[{}]".format(p) for p in node_find_target(provenance.toplevel, self)] + ["[{}]".format(index)]
             raise LoadError(LoadErrorReason.INVALID_DATA,
                             "{}: Value of '{}' is not of the expected type '{}'"
                             .format(provenance, path, SequenceNode.__name__))
@@ -670,101 +670,6 @@ cpdef ProvenanceInformation node_get_provenance(Node node, str key=None, list in
     return ProvenanceInformation(nodeish)
 
 
-# node_get()
-#
-# Fetches a value from a dictionary node and checks it for
-# an expected value. Use default_value when parsing a value
-# which is only optionally supplied.
-#
-# Args:
-#    node (dict): The dictionary node
-#    expected_type (type): The expected type for the value being searched
-#    key (str): The key to get a value for in node
-#    indices (list of ints): Optionally decend into lists of lists
-#    default_value: Optionally return this value if the key is not found
-#    allow_none: (bool): Allow None to be a valid value
-#
-# Returns:
-#    The value if found in node, otherwise default_value is returned
-#
-# Raises:
-#    LoadError, when the value found is not of the expected type
-#
-# Note:
-#    Returned strings are stripped of leading and trailing whitespace
-#
-cpdef object node_get(Node node, object expected_type, str key, list indices=None, object default_value=_sentinel, bint allow_none=False):
-    if indices is None:
-        value = node.value.get(key, _sentinel)
-
-        if value is _sentinel:
-            if default_value is _sentinel:
-                provenance = node_get_provenance(node)
-                raise LoadError(LoadErrorReason.INVALID_DATA,
-                                "{}: Dictionary did not contain expected key '{}'".format(provenance, key))
-
-            value = _create_node(default_value, _SYNTHETIC_FILE_INDEX, 0, next_synthetic_counter())
-    else:
-        # Implied type check of the element itself
-        # No need to synthesise useful node content as we destructure it immediately
-        value = SequenceNode(node_get(node, list, key), _SYNTHETIC_FILE_INDEX, 0, 0)
-        for index in indices:
-            value = value.value[index]
-            # FIXME: this should always be nodes, we should be able to remove that
-            if type(value) not in [Node, MappingNode, SequenceNode]:
-                value = _create_node(value, _SYNTHETIC_FILE_INDEX, 0, 0)
-
-    # Optionally allow None as a valid value for any type
-    if value.value is None and (allow_none or default_value is None):
-        return None
-
-    if (expected_type is not None) and (type(value.value) is not expected_type):
-        # Attempt basic conversions if possible, typically we want to
-        # be able to specify numeric values and convert them to strings,
-        # but we dont want to try converting dicts/lists
-        try:
-            if expected_type == bool and type(value.value) is str:
-                # Dont coerce booleans to string, this makes "False" strings evaluate to True
-                # We don't structure into full nodes since there's no need.
-                if value.value in ('True', 'true'):
-                    value = ScalarNode(True, _SYNTHETIC_FILE_INDEX, 0, 0)
-                elif value.value in ('False', 'false'):
-                    value = ScalarNode(False, _SYNTHETIC_FILE_INDEX, 0, 0)
-                else:
-                    raise ValueError()
-            elif not (expected_type == list or
-                      expected_type == dict or
-                      isinstance(value.value, (list, dict))):
-                value = _create_node(expected_type(value.value), _SYNTHETIC_FILE_INDEX, 0, 0)
-            else:
-                raise ValueError()
-        except (ValueError, TypeError):
-            provenance = node_get_provenance(node, key=key, indices=indices)
-            if indices:
-                path = [key, *["[{:d}]".format(i) for i in indices]]
-                path = "".join(path)
-            else:
-                path = key
-            raise LoadError(LoadErrorReason.INVALID_DATA,
-                            "{}: Value of '{}' is not of the expected type '{}'"
-                            .format(provenance, path, expected_type.__name__))
-
-    # Now collapse lists, and scalars, to their value, leaving nodes as-is
-    if type(value.value) is not dict:
-        value = value.value
-
-    # Trim it at the bud, let all loaded strings from yaml be stripped of whitespace
-    if type(value) is str:
-        value = value.strip()
-
-    elif type(value) is list:
-        # Now we create a fresh list which unwraps the str and list types
-        # semi-recursively.
-        value = __trim_list_provenance(value)
-
-    return value
-
-
 cdef list __trim_list_provenance(list value):
     cdef list ret = []
     cdef Node entry
diff --git a/src/buildstream/element.py b/src/buildstream/element.py
index 1bbc7af2d..7efe32309 100644
--- a/src/buildstream/element.py
+++ b/src/buildstream/element.py
@@ -532,13 +532,12 @@ class Element(Plugin):
           :class:`.LoadError`
 
         """
-        value = self.node_get_member(node, list, member_name)
         ret = []
-        for index, x in enumerate(value):
+        for value in node.get_sequence(member_name):
             try:
-                ret.append(self.__variables.subst(x))
+                ret.append(self.__variables.subst(value.as_str()))
             except LoadError as e:
-                provenance = _yaml.node_get_provenance(node, key=member_name, indices=[index])
+                provenance = _yaml.node_get_provenance(value)
                 raise LoadError(e.reason, '{}: {}'.format(provenance, e), detail=e.detail) from e
         return ret
 
@@ -2816,7 +2815,7 @@ class Element(Plugin):
         # If this ever changes, things will go wrong unexpectedly.
         if not self.__whitelist_regex:
             bstdata = self.get_public_data('bst')
-            whitelist = _yaml.node_get(bstdata, list, 'overlap-whitelist', default_value=[])
+            whitelist = bstdata.get_sequence('overlap-whitelist', default=[]).as_str_list()
             whitelist_expressions = [utils._glob2re(self.__variables.subst(exp.strip())) for exp in whitelist]
             expression = ('^(?:' + '|'.join(whitelist_expressions) + ')$')
             self.__whitelist_regex = re.compile(expression)
diff --git a/src/buildstream/plugins/elements/compose.py b/src/buildstream/plugins/elements/compose.py
index b2e52170e..a9f18875f 100644
--- a/src/buildstream/plugins/elements/compose.py
+++ b/src/buildstream/plugins/elements/compose.py
@@ -66,8 +66,8 @@ class ComposeElement(Element):
         # We name this variable 'integration' only to avoid
         # collision with the Element.integrate() method.
         self.integration = node.get_bool('integrate')
-        self.include = self.node_get_member(node, list, 'include')
-        self.exclude = self.node_get_member(node, list, 'exclude')
+        self.include = node.get_sequence('include').as_str_list()
+        self.exclude = node.get_sequence('exclude').as_str_list()
         self.include_orphans = node.get_bool('include-orphans')
 
     def preflight(self):
diff --git a/src/buildstream/plugins/elements/filter.py b/src/buildstream/plugins/elements/filter.py
index e62a9d49b..bba56f351 100644
--- a/src/buildstream/plugins/elements/filter.py
+++ b/src/buildstream/plugins/elements/filter.py
@@ -171,8 +171,8 @@ class FilterElement(Element):
             'include', 'exclude', 'include-orphans'
         ])
 
-        self.include = self.node_get_member(node, list, 'include')
-        self.exclude = self.node_get_member(node, list, 'exclude')
+        self.include = node.get_sequence('include').as_str_list()
+        self.exclude = node.get_sequence('exclude').as_str_list()
         self.include_orphans = node.get_bool('include-orphans')
         self.include_provenance = self.node_provenance(node, member_name='include')
         self.exclude_provenance = self.node_provenance(node, member_name='exclude')
diff --git a/src/buildstream/plugins/elements/script.py b/src/buildstream/plugins/elements/script.py
index df03bad17..1c694060c 100644
--- a/src/buildstream/plugins/elements/script.py
+++ b/src/buildstream/plugins/elements/script.py
@@ -46,7 +46,7 @@ class ScriptElement(buildstream.ScriptElement):
     BST_VIRTUAL_DIRECTORY = True
 
     def configure(self, node):
-        for n in self.node_get_member(node, list, 'layout', []):
+        for n in node.get_sequence('layout', []):
             dst = self.node_subst_member(n, 'destination')
             elm = self.node_subst_member(n, 'element', None)
             self.layout_add(elm, dst)
diff --git a/src/buildstream/plugins/sources/pip.py b/src/buildstream/plugins/sources/pip.py
index 816b9e95b..627f26397 100644
--- a/src/buildstream/plugins/sources/pip.py
+++ b/src/buildstream/plugins/sources/pip.py
@@ -114,14 +114,14 @@ class PipSource(Source):
         self.ref = node.get_str('ref', None)
         self.original_url = node.get_str('url', _PYPI_INDEX_URL)
         self.index_url = self.translate_url(self.original_url)
-        self.packages = self.node_get_member(node, list, 'packages', [])
-        self.requirements_files = self.node_get_member(node, list, 'requirements-files', [])
+        self.packages = node.get_sequence('packages', []).as_str_list()
+        self.requirements_files = node.get_sequence('requirements-files', []).as_str_list()
 
         if not (self.packages or self.requirements_files):
             raise SourceError("{}: Either 'packages' or 'requirements-files' must be specified". format(self))
 
     def preflight(self):
-        # Try to find a pip version that supports download command
+        # Try to find a pip version that spports download command
         self.host_pip = None
         for python in reversed(_PYTHON_VERSIONS):
             try:
diff --git a/src/buildstream/sandbox/_sandboxremote.py b/src/buildstream/sandbox/_sandboxremote.py
index fbba17f3f..965aea155 100644
--- a/src/buildstream/sandbox/_sandboxremote.py
+++ b/src/buildstream/sandbox/_sandboxremote.py
@@ -173,7 +173,7 @@ class SandboxRemote(Sandbox):
 
             for tls_key in tls_keys:
                 if tls_key in config:
-                    _yaml.node_set(config, tls_key, resolve_path(_yaml.node_get(config, str, tls_key)))
+                    _yaml.node_set(config, tls_key, resolve_path(config.get_str(tls_key)))
 
         return RemoteExecutionSpec(*[_yaml.node_sanitize(conf) for conf in service_configs])
 
diff --git a/src/buildstream/testing/_sourcetests/mirror.py b/src/buildstream/testing/_sourcetests/mirror.py
index d682bb2ef..afbadbef7 100644
--- a/src/buildstream/testing/_sourcetests/mirror.py
+++ b/src/buildstream/testing/_sourcetests/mirror.py
@@ -357,9 +357,9 @@ def test_mirror_track_upstream_present(cli, tmpdir, datafiles, kind):
 
     # Tracking tries upstream first. Check the ref is from upstream.
     new_element = _yaml.load(element_path)
-    source = _yaml.node_get(new_element, dict, 'sources', [0])
+    source = new_element.get_sequence('sources').mapping_at(0)
     if 'ref' in source:
-        assert _yaml.node_get(source, str, 'ref') == upstream_ref
+        assert source.get_str('ref') == upstream_ref
 
 
 @pytest.mark.datafiles(DATA_DIR)
@@ -422,6 +422,6 @@ def test_mirror_track_upstream_absent(cli, tmpdir, datafiles, kind):
 
     # Check that tracking fell back to the mirror
     new_element = _yaml.load(element_path)
-    source = _yaml.node_get(new_element, dict, 'sources', [0])
+    source = new_element.get_sequence('sources').mapping_at(0)
     if 'ref' in source:
-        assert _yaml.node_get(source, str, 'ref') == mirror_ref
+        assert source.get_str('ref') == mirror_ref
diff --git a/src/buildstream/testing/_sourcetests/track.py b/src/buildstream/testing/_sourcetests/track.py
index 668ea29e5..08173e79b 100644
--- a/src/buildstream/testing/_sourcetests/track.py
+++ b/src/buildstream/testing/_sourcetests/track.py
@@ -321,13 +321,13 @@ def test_track_include(cli, tmpdir, datafiles, ref_storage, kind):
 
         # Get all of the sources
         assert 'sources' in new_sources
-        sources_list = _yaml.node_get(new_sources, list, 'sources')
+        sources_list = new_sources.get_sequence('sources')
         assert len(sources_list) == 1
 
         # Get the first source from the sources list
-        new_source = _yaml.node_get(new_sources, dict, 'sources', indices=[0])
+        new_source = sources_list.mapping_at(0)
         assert 'ref' in new_source
-        assert ref == _yaml.node_get(new_source, str, 'ref')
+        assert ref == new_source.get_scalar('ref').as_str()
 
 
 @pytest.mark.datafiles(DATA_DIR)
diff --git a/tests/elements/filter.py b/tests/elements/filter.py
index 8292c09bb..f9c80afff 100644
--- a/tests/elements/filter.py
+++ b/tests/elements/filter.py
@@ -239,7 +239,7 @@ def test_filter_track(datafiles, cli, tmpdir):
 
     # Now check that a ref field exists
     new_input = _yaml.load(input_file)
-    source_node = _yaml.node_get(new_input, dict, 'sources', indices=[0])
+    source_node = new_input.get_sequence('sources').mapping_at(0)
     new_input_ref = source_node.get_str('ref')
     assert new_input_ref == ref
 
@@ -294,7 +294,7 @@ def test_filter_track_excepted(datafiles, cli, tmpdir):
 
     # Now check that a ref field exists
     new_input = _yaml.load(input_file)
-    source_node = _yaml.node_get(new_input, dict, 'sources', indices=[0])
+    source_node = new_input.get_sequence('sources').mapping_at(0)
     assert 'ref' not in source_node
 
 
@@ -348,7 +348,7 @@ def test_filter_track_multi_to_one(datafiles, cli, tmpdir):
 
     # Now check that a ref field exists
     new_input = _yaml.load(input_file)
-    source_node = _yaml.node_get(new_input, dict, 'sources', indices=[0])
+    source_node = new_input.get_sequence('sources').mapping_at(0)
     new_ref = source_node.get_str('ref')
     assert new_ref == ref
 
@@ -413,12 +413,12 @@ def test_filter_track_multi(datafiles, cli, tmpdir):
 
     # Now check that a ref field exists
     new_input = _yaml.load(input_file)
-    source_node = _yaml.node_get(new_input, dict, 'sources', indices=[0])
+    source_node = new_input.get_sequence('sources').mapping_at(0)
     new_ref = source_node.get_str('ref')
     assert new_ref == ref
 
     new_input2 = _yaml.load(input2_file)
-    source_node2 = _yaml.node_get(new_input2, dict, 'sources', indices=[0])
+    source_node2 = new_input2.get_sequence('sources').mapping_at(0)
     new_ref2 = source_node2.get_str('ref')
     assert new_ref2 == ref
 
@@ -482,11 +482,11 @@ def test_filter_track_multi_exclude(datafiles, cli, tmpdir):
 
     # Now check that a ref field exists
     new_input = _yaml.load(input_file)
-    source_node = _yaml.node_get(new_input, dict, 'sources', indices=[0])
+    source_node = new_input.get_sequence('sources').mapping_at(0)
     assert 'ref' not in source_node
 
     new_input2 = _yaml.load(input2_file)
-    source_node2 = _yaml.node_get(new_input2, dict, 'sources', indices=[0])
+    source_node2 = new_input2.get_sequence('sources').mapping_at(0)
     new_ref2 = source_node2.get_str('ref')
     assert new_ref2 == ref
 
diff --git a/tests/frontend/cross_junction_workspace.py b/tests/frontend/cross_junction_workspace.py
index 974aba4bd..38aafa558 100644
--- a/tests/frontend/cross_junction_workspace.py
+++ b/tests/frontend/cross_junction_workspace.py
@@ -75,10 +75,12 @@ def test_list_cross_junction(cli, tmpdir):
     result.assert_success()
 
     loaded = _yaml.load_data(result.output)
-    workspaces = _yaml.node_get(loaded, list, 'workspaces')
+    workspaces = loaded.get_sequence('workspaces')
     assert len(workspaces) == 1
-    assert 'element' in workspaces[0]
-    assert workspaces[0].get_str('element') == element
+    first_workspace = workspaces.mapping_at(0)
+
+    assert 'element' in first_workspace
+    assert first_workspace.get_str('element') == element
 
 
 def test_close_cross_junction(cli, tmpdir):
@@ -96,7 +98,7 @@ def test_close_cross_junction(cli, tmpdir):
     result.assert_success()
 
     loaded = _yaml.load_data(result.output)
-    workspaces = _yaml.node_get(loaded, list, 'workspaces')
+    workspaces = loaded.get_sequence('workspaces')
     assert not workspaces
 
 
@@ -114,7 +116,7 @@ def test_close_all_cross_junction(cli, tmpdir):
     result.assert_success()
 
     loaded = _yaml.load_data(result.output)
-    workspaces = _yaml.node_get(loaded, list, 'workspaces')
+    workspaces = loaded.get_sequence('workspaces')
     assert not workspaces
 
 
diff --git a/tests/frontend/project/sources/fetch_source.py b/tests/frontend/project/sources/fetch_source.py
index 9a873d1fe..7c0df4595 100644
--- a/tests/frontend/project/sources/fetch_source.py
+++ b/tests/frontend/project/sources/fetch_source.py
@@ -38,7 +38,7 @@ class FetchFetcher(SourceFetcher):
 class FetchSource(Source):
     # Read config to know which URLs to fetch
     def configure(self, node):
-        self.original_urls = self.node_get_member(node, list, 'urls')
+        self.original_urls = node.get_sequence('urls').as_str_list()
         self.output_file = node.get_str('output-text')
         self.fetch_succeeds = {}
         if 'fetch-succeeds' in node:
diff --git a/tests/frontend/workspace.py b/tests/frontend/workspace.py
index 339f0d496..b240e5728 100644
--- a/tests/frontend/workspace.py
+++ b/tests/frontend/workspace.py
@@ -184,7 +184,7 @@ def test_open_bzr_customize(cli, tmpdir, datafiles):
 
     # Check that the correct origin branch is set
     element_config = _yaml.load(os.path.join(project, "elements", element_name))
-    source_config = _yaml.node_get(element_config, dict, 'sources', [0])
+    source_config = element_config.get_sequence('sources').mapping_at(0)
     output = subprocess.check_output(["bzr", "info"], cwd=workspace)
     stripped_url = source_config.get_str('url').lstrip("file:///")
     expected_output_str = ("checkout of branch: /{}/{}"
@@ -608,10 +608,10 @@ def test_list(cli, tmpdir, datafiles):
     result.assert_success()
 
     loaded = _yaml.load_data(result.output)
-    workspaces = _yaml.node_get(loaded, list, 'workspaces')
+    workspaces = loaded.get_sequence('workspaces')
     assert len(workspaces) == 1
 
-    space = workspaces[0]
+    space = workspaces.mapping_at(0)
     assert space.get_str('element') == element_name
     assert space.get_str('directory') == workspace
 
@@ -1132,7 +1132,7 @@ def test_external_track(cli, datafiles, tmpdir_factory, guess_element):
     # Delete the ref from the source so that we can detect if the
     # element has been tracked
     element_contents = _yaml.load(element_file)
-    _yaml.node_del(_yaml.node_get(element_contents, dict, 'sources', [0]), 'ref')
+    _yaml.node_del(element_contents.get_sequence('sources').mapping_at(0), 'ref')
     _yaml.dump(element_contents, element_file)
 
     result = cli.run(project=project, args=['-C', workspace, 'source', 'track', *arg_elm])
@@ -1140,7 +1140,7 @@ def test_external_track(cli, datafiles, tmpdir_factory, guess_element):
 
     # Element is tracked now
     element_contents = _yaml.load(element_file)
-    assert 'ref' in _yaml.node_get(element_contents, dict, 'sources', [0])
+    assert 'ref' in element_contents.get_sequence('sources').mapping_at(0)
 
 
 @pytest.mark.datafiles(DATA_DIR)
diff --git a/tests/internals/yaml.py b/tests/internals/yaml.py
index 0e747fa48..aa83d949a 100644
--- a/tests/internals/yaml.py
+++ b/tests/internals/yaml.py
@@ -103,11 +103,11 @@ def test_node_get(datafiles):
     base = _yaml.load(filename)
     assert base.value.get('kind').value == 'pony'
 
-    children = _yaml.node_get(base, list, 'children')
-    assert isinstance(children, list)
+    children = base.get_sequence('children')
+    assert isinstance(children, _yaml.SequenceNode)
     assert len(children) == 7
 
-    child = _yaml.node_get(base, dict, 'children', indices=[6])
+    child = base.get_sequence('children').mapping_at(6)
     assert_provenance(filename, 20, 8, child, 'mood')
 
     extra = base.get_mapping('extra')
@@ -146,7 +146,7 @@ def test_node_set_overwrite(datafiles):
     assert base.get_str('kind') == 'cow'
 
     # Overwrite a list as a string
-    assert _yaml.node_get(base, list, 'moods') == ['happy', 'sad']
+    assert base.get_sequence('moods').as_str_list() == ['happy', 'sad']
     _yaml.node_set(base, 'moods', 'unemotional')
     assert base.get_str('moods') == 'unemotional'
 
@@ -160,13 +160,11 @@ def test_node_set_list_element(datafiles):
 
     base = _yaml.load(filename)
 
-    assert _yaml.node_get(base, list, 'moods') == ['happy', 'sad']
-    assert _yaml.node_get(base, str, 'moods', indices=[0]) == 'happy'
+    assert base.get_sequence('moods').as_str_list() == ['happy', 'sad']
 
     _yaml.node_set(base, 'moods', 'confused', indices=[0])
 
-    assert _yaml.node_get(base, list, 'moods') == ['confused', 'sad']
-    assert _yaml.node_get(base, str, 'moods', indices=[0]) == 'confused'
+    assert base.get_sequence('moods').as_str_list() == ['confused', 'sad']
 
 
 # Really this is testing _yaml.node_copy(), we want to
@@ -254,9 +252,9 @@ def test_list_composition(datafiles, filename, tmpdir,
 
     _yaml.composite_dict(base, overlay)
 
-    children = _yaml.node_get(base, list, 'children')
+    children = base.get_sequence('children')
     assert len(children) == length
-    child = children[index]
+    child = children.mapping_at(index)
 
     assert child.get_str('mood') == mood
     assert_provenance(prov_file, prov_line, prov_col, child, 'mood')
@@ -272,7 +270,7 @@ def test_list_deletion(datafiles):
     overlay = _yaml.load(overlay, shortname='listoverwriteempty.yaml')
     _yaml.composite_dict(base, overlay)
 
-    children = _yaml.node_get(base, list, 'children')
+    children = base.get_sequence('children')
     assert not children
 
 
@@ -286,8 +284,8 @@ def test_nonexistent_list_extension(datafiles):
 
     _yaml.node_extend_list(base, 'todo', 3, 'empty')
 
-    assert len(_yaml.node_get(base, list, 'todo')) == 3
-    assert _yaml.node_get(base, list, 'todo') == ['empty', 'empty', 'empty']
+    assert len(base.get_sequence('todo')) == 3
+    assert base.get_sequence('todo').as_str_list() == ['empty', 'empty', 'empty']
 
 
 # Tests for deep list composition
@@ -390,9 +388,9 @@ def test_list_composition_twice(datafiles, tmpdir, filename1, filename2,
     _yaml.composite_dict(base, overlay1)
     _yaml.composite_dict(base, overlay2)
 
-    children = _yaml.node_get(base, list, 'children')
+    children = base.get_sequence('children')
     assert len(children) == length
-    child = children[index]
+    child = children.mapping_at(index)
 
     assert child.get_str('mood') == mood
     assert_provenance(prov_file, prov_line, prov_col, child, 'mood')
@@ -407,9 +405,9 @@ def test_list_composition_twice(datafiles, tmpdir, filename1, filename2,
     _yaml.composite_dict(overlay1, overlay2)
     _yaml.composite_dict(base, overlay1)
 
-    children = _yaml.node_get(base, list, 'children')
+    children = base.get_sequence('children')
     assert len(children) == length
-    child = children[index]
+    child = children.mapping_at(index)
 
     assert child.get_str('mood') == mood
     assert_provenance(prov_file, prov_line, prov_col, child, 'mood')
diff --git a/tests/sources/git.py b/tests/sources/git.py
index e3f803469..69155e02b 100644
--- a/tests/sources/git.py
+++ b/tests/sources/git.py
@@ -760,7 +760,7 @@ def test_track_fetch(cli, tmpdir, datafiles, ref_format, tag, extra_commit):
     result.assert_success()
 
     element = _yaml.load(element_path)
-    new_ref = _yaml.node_get(element, dict, 'sources', [0]).get_str('ref')
+    new_ref = element.get_sequence('sources').mapping_at(0).get_str('ref')
 
     if ref_format == 'git-describe' and tag:
         # Check and strip prefix
@@ -849,7 +849,7 @@ def test_git_describe(cli, tmpdir, datafiles, ref_storage, tag_type):
 
     if ref_storage == 'inline':
         element = _yaml.load(element_path)
-        tags = _yaml.node_get(_yaml.node_get(element, dict, 'sources', [0]), list, 'tags')
+        tags = element.get_sequence('sources').mapping_at(0).get_sequence('tags')
         assert len(tags) == 2
         for tag in tags:
             assert 'tag' in tag
@@ -962,11 +962,11 @@ def test_git_describe_head_is_tagged(cli, tmpdir, datafiles, ref_storage, tag_ty
 
     if ref_storage == 'inline':
         element = _yaml.load(element_path)
-        source = _yaml.node_get(element, dict, 'sources', indices=[0])
-        tags = _yaml.node_get(source, list, 'tags')
+        source = element.get_sequence('sources').mapping_at(0)
+        tags = source.get_sequence('tags')
         assert len(tags) == 1
 
-        tag = _yaml.node_get(source, dict, 'tags', indices=[0])
+        tag = source.get_sequence('tags').mapping_at(0)
         assert 'tag' in tag
         assert 'commit' in tag
         assert 'annotated' in tag
@@ -1125,7 +1125,7 @@ def test_default_do_not_track_tags(cli, tmpdir, datafiles):
     result.assert_success()
 
     element = _yaml.load(element_path)
-    source = _yaml.node_get(element, dict, 'sources', indices=[0])
+    source = element.get_sequence('sources').mapping_at(0)
     assert 'tags' not in source