Added ExistsAction

Author: idle-code

TreeRoot.py

@@ -18,7 +18,7 @@ def _install_actions(self):
         self.install_action(GetAction())
         self.install_action(SetAction())
         self.install_action(ListAction())
-        self.install_action(ActionNode('exists', BasicActions.exists))
+        self.install_action(ExistsAction())
         self.install_action(ActionNode('create', BasicActions.create))
         self.install_action(ActionNode('remove', BasicActions.remove))
 

actions/BasicActions.py

@@ -43,6 +43,13 @@ def __call__(self, target: Node, new_value):
         target.set(new_value)
 
 
+class ExistsAction(ActionNode):
+    def __init__(self):
+        super().__init__(path='exists')
+
+    def __call__(self, target: Node, node_name: str) -> bool:
+        return target.contains(node_name)
+
 class ListAction(ActionNode):
     def __init__(self):
         super().__init__(path='list')

tests/action_tests/ExistsActionTests.py

@@ -0,0 +1,37 @@
+import unittest
+
+from Node import Node
+from NodePath import NodePath
+from actions.BasicActions import ExistsAction
+
+
+class ExistsActionTests(unittest.TestCase):
+    def setUp(self):
+        self.root = Node()
+        self.root.append(Node(123), 'integer')
+        self.root.append(Node('foobar'), 'string')
+        self.root.append(Node(), 'empty')
+
+        self.exists = ExistsAction()
+
+    def test_action_name(self):
+        self.assertEqual(NodePath('exists'), self.exists.path)
+
+    def test_existing(self):
+        self.assertTrue(self.exists(self.root, 'integer'))
+        self.assertTrue(self.exists(self.root, 'empty'))
+
+    def test_nonexistent(self):
+        self.assertFalse(self.exists(self.root, 'unknown'))
+
+    def test_surplus_arguments(self):
+        with self.assertRaises(TypeError):
+            self.exists(self.root, 'unknown', 'name')
+
+    def test_no_argument(self):
+        with self.assertRaises(TypeError):
+            self.exists(self.root)
+
+
+if __name__ == '__main__':
+    unittest.main()

tests/action_tests/SetActionTests.py

@@ -32,6 +32,10 @@ def test_set_none(self):
         with self.assertRaises(TypeError):
             self.set(self.root['empty'], 23)
 
+    def test_no_arguments(self):
+        with self.assertRaises(TypeError):
+            self.set(self.root['integer'])
+
     def test_too_many_arguments(self):
         with self.assertRaises(TypeError):
             self.set(self.root['integer'], 1, 2, 3)