Fix #36 -- switch to graphviz 0.18 (#37)

* Fix #36 -- switch to graphviz 0.18

Use staticmethods instead of "%" operator. This reflects xflr6/graphviz@17df613

* Use quoting instead of lang

Reflects xflr6/graphviz@673261d

* Use new `encoding` argument instead of manual decoding

https://github.com/xflr6/graphviz/blob/master/CHANGES.rst#version-018
>Add optional keyword-only encoding argument to pipe(). Returns the decoded stdout from the rendering process (e.g. format='svg'). Delegates encoding/decoding to subprocess in the common case (input and output encoding are the same, e.g. default encoding='utf-8'). Used by the Jupyter notebook integration.

* Adjust tests to handle newlines

https://github.com/xflr6/graphviz/blob/master/CHANGES.rst#version-018
>Change of undocumented behaviour: When iterating over a Graph, Digraph, or Source instance, the yielded lines now include a final newline ('\n'). This mimics iteration over file object lines in text mode.

* Pin graphviz>=0.18

* Blackify

* Fix one more test

joeflow/models.py

@@ -236,7 +236,7 @@ def get_graph_svg(cls):
         """
         graph = cls.get_graph()
         graph.format = "svg"
-        return SafeString(graph.pipe().decode("utf-8"))  # nosec
+        return SafeString(graph.pipe(encoding="utf-8"))  # nosec
 
     get_graph_svg.short_description = t("graph")
 
@@ -326,7 +326,7 @@ def get_instance_graph_svg(self, output_format="svg"):
         """
         graph = self.get_instance_graph()
         graph.format = output_format
-        return SafeString(graph.pipe().decode("utf-8"))  # nosec
+        return SafeString(graph.pipe(encoding="utf-8"))  # nosec
 
     get_instance_graph_svg.short_description = t("instance graph")
 

joeflow/utils.py

@@ -44,20 +44,20 @@ def __init__(self, *args, **kwargs):
     def __iter__(self, subgraph=False):
         """Yield the DOT source code line by line (as graph or subgraph)."""
         if self.comment:
-            yield self._comment % self.comment
+            yield self._comment(self.comment)
 
         if subgraph:
             if self.strict:
                 raise ValueError("subgraphs cannot be strict")
             head = self._subgraph if self.name else self._subgraph_plain
         else:
             head = self._head_strict if self.strict else self._head
-        yield head % (self._quote(self.name) + " " if self.name else "")
+        yield head(self._quote(self.name) + " " if self.name else "")
 
         for kw in ("graph", "node", "edge"):
             attrs = getattr(self, "%s_attr" % kw)
             if attrs:
-                yield self._attr % (kw, self._attr_list(None, attrs))
+                yield self._attr(kw, self._attr_list(None, attrs))
 
         yield from self.body
 
@@ -66,16 +66,16 @@ def __iter__(self, subgraph=False):
             label = attrs.pop("label", None)
             _attributes = attrs.pop("_attributes", None)
             attr_list = self._attr_list(label, attrs, _attributes)
-            yield self._node % (name, attr_list)
+            yield self._node(name, attr_list)
 
         for edge, attrs in sorted(self._edges.items()):
-            head_name, tail_name = edge
+            tail_name, head_name = edge
             tail_name = self._quote_edge(tail_name)
             head_name = self._quote_edge(head_name)
             label = attrs.pop("label", None)
             _attributes = attrs.pop("_attributes", None)
             attr_list = self._attr_list(label, attrs, _attributes)
-            yield self._edge % (head_name, tail_name, attr_list)
+            yield self._edge(tail=tail_name, head=head_name, attr=attr_list)
 
         yield self._tail
 
@@ -89,10 +89,10 @@ def edge(self, tail_name, head_name, **attrs):
     def _quote(identifier, *args, **kwargs):
         """Remove underscores from labels."""
         identifier = identifier.replace("_", " ")
-        return gv.lang.quote(identifier, *args, **kwargs)
+        return gv.quoting.quote(identifier, *args, **kwargs)
 
     @staticmethod
     def _quote_edge(identifier):
         """Remove underscores from labels."""
         identifier = identifier.replace("_", " ")
-        return gv.lang.quote_edge(identifier)
+        return gv.quoting.quote_edge(identifier)

setup.cfg

@@ -46,7 +46,7 @@ packages = joeflow
 install_requires =
     django>=2.2
     django-appconf
-    graphviz
+    graphviz>=0.18
 setup_requires =
     setuptools_scm
     sphinx

tests/test_models.py

@@ -109,7 +109,7 @@ def test_get_graph(self, fixturedir):
         with open(str(fixturedir / "simpleworkflow.dot")) as fp:
             expected_graph = fp.read().splitlines()
         print(str(graph))
-        assert set(graph) == set(expected_graph)
+        assert set(str(graph).splitlines()) == set(expected_graph)
 
     def test_get_graph_svg(self, fixturedir):
         svg = workflows.SimpleWorkflow.get_graph_svg()
@@ -121,7 +121,9 @@ def test_get_instance_graph(self, db, fixturedir):
         graph = wf.get_instance_graph()
         print(str(graph))
         with open(str(fixturedir / "simpleworkflow_instance.dot")) as fp:
-            assert set(graph) == set(fp.read().replace("{url}", task_url).splitlines())
+            assert set(str(graph).splitlines()) == set(
+                fp.read().replace("{url}", task_url).splitlines()
+            )
 
     def test_get_instance_graph__override(
         self, db, stub_worker, fixturedir, admin_client
@@ -136,14 +138,14 @@ def test_get_instance_graph__override(
         print(str(graph))
 
         assert (
-            f'\t"{task.name} {task.pk}" [peripheries=1 style="filled, rounded, dashed"]'
+            f'\t"{task.name} {task.pk}" [peripheries=1 style="filled, rounded, dashed"]\n'
             in list(graph)
         )
         assert (
-            f'\t"save the princess" -> "{task.name} {task.pk}" [style=dashed]'
+            f'\t"save the princess" -> "{task.name} {task.pk}" [style=dashed]\n'
             in list(graph)
         )
-        assert f'\t"{task.name} {task.pk}" -> end [style=dashed]' in list(graph)
+        assert f'\t"{task.name} {task.pk}" -> end [style=dashed]\n' in list(graph)
 
     def test_get_instance_graph__obsolete(self, db, fixturedir, admin_client):
         workflow = workflows.SimpleWorkflow.objects.create()
@@ -159,8 +161,8 @@ def test_get_instance_graph__obsolete(self, db, fixturedir, admin_client):
             '\tobsolete [color=black fontcolor=black peripheries=1 style="filled, dashed, bold"]'
             in str(graph)
         )
-        assert '\t"start method" -> obsolete [style=dashed]' in list(graph)
-        assert "\tobsolete -> end [style=dashed]" in list(graph)
+        assert '\t"start method" -> obsolete [style=dashed]\n' in list(graph)
+        assert "\tobsolete -> end [style=dashed]\n" in list(graph)
 
     def test_get_instance_graph_svg(self, db, fixturedir):
         wf = workflows.SimpleWorkflow.start_method()

tests/test_utils.py

@@ -6,30 +6,30 @@ def test_node(self):
         graph = NoDashDiGraph()
         graph.node("foo", color="blue")
         assert list(graph) == [
-            "digraph {",
-            "\tfoo [color=blue]",
-            "}",
+            "digraph {\n",
+            "\tfoo [color=blue]\n",
+            "}\n",
         ]
         graph.node("foo", color="red")
         assert list(graph) == [
-            "digraph {",
-            "\tfoo [color=red]",
-            "}",
+            "digraph {\n",
+            "\tfoo [color=red]\n",
+            "}\n",
         ]
 
     def test_edge(self):
         graph = NoDashDiGraph()
         graph.edge("foo", "bar", color="blue")
         assert list(graph) == [
-            "digraph {",
-            "\tfoo -> bar [color=blue]",
-            "}",
+            "digraph {\n",
+            "\tfoo -> bar [color=blue]\n",
+            "}\n",
         ]
         graph.edge("foo", "bar", color="red")
         assert list(graph) == [
-            "digraph {",
-            "\tfoo -> bar [color=red]",
-            "}",
+            "digraph {\n",
+            "\tfoo -> bar [color=red]\n",
+            "}\n",
         ]
 
     def test_iter(self):
@@ -40,13 +40,13 @@ def test_iter(self):
         graph.comment = "This is a comment."
         print(str(graph))
         assert list(graph.__iter__()) == [
-            "// This is a comment.",
-            "digraph {",
-            "\tnode [style=filled]",
-            "\tbar [color=green]",
-            "\tfoo [color=red]",
-            "\tfoo -> bar [color=blue]",
-            "}",
+            "// This is a comment.\n",
+            "digraph {\n",
+            "\tnode [style=filled]\n",
+            "\tbar [color=green]\n",
+            "\tfoo [color=red]\n",
+            "\tfoo -> bar [color=blue]\n",
+            "}\n",
         ]
 
     def test_iter__subgraph(self):
@@ -57,13 +57,13 @@ def test_iter__subgraph(self):
         graph.comment = "This is a comment."
         print(str(graph))
         assert list(graph.__iter__(subgraph=True)) == [
-            "// This is a comment.",
-            "{",
-            "\tnode [style=filled]",
-            "\tbar [color=green]",
-            "\tfoo [color=red]",
-            "\tfoo -> bar [color=blue]",
-            "}",
+            "// This is a comment.\n",
+            "{\n",
+            "\tnode [style=filled]\n",
+            "\tbar [color=green]\n",
+            "\tfoo [color=red]\n",
+            "\tfoo -> bar [color=blue]\n",
+            "}\n",
         ]
 
     def test_quote(self):