graph: added simple test

tests/_graphviz_test.py

@@ -0,0 +1,44 @@
+# yamify - define family trees in YAML
+#
+# Copyright (C) 2020 Fabian Peter Hammerle <fabian@hammerle.me>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from yamily import Person, PersonCollection
+from yamily._graphviz import digraph
+
+
+def test_digraph_single_family():
+    collection = PersonCollection()
+    child = Person("child")
+    child.father = Person("father")
+    child.mother = Person("mother")
+    collection.add_person(child)
+    graph = digraph(collection)
+    expected_graph = """digraph yamily {
+	subgraph cluster_mother {
+		rank=same style=invisible
+		mother [label=mother shape=box]
+		"relation-father-mother" [shape=point width=0]
+		father -> "relation-father-mother" [arrowhead=none constraint=False]
+		mother -> "relation-father-mother" [arrowhead=none constraint=False]
+		father [label=father shape=box]
+	}
+	subgraph cluster_child {
+		rank=same style=invisible
+		child [label=child shape=box]
+	}
+	"relation-father-mother" -> child
+}"""
+    assert graph.source == expected_graph