From 61a276f49a7696ee2794739fb966ae02bdead0a3 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Wed, 28 Aug 2019 11:03:56 +0200
Subject: [PATCH] tests: add some ModifierButtons unit tests

---
 tests/putil/test_modifierbuttons.py | 35 +++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 tests/putil/test_modifierbuttons.py

diff --git a/tests/putil/test_modifierbuttons.py b/tests/putil/test_modifierbuttons.py
new file mode 100644
index 0000000000..289966d1df
--- /dev/null
+++ b/tests/putil/test_modifierbuttons.py
@@ -0,0 +1,35 @@
+from panda3d.core import ModifierButtons
+
+
+def test_modifierbuttons_empty():
+    # Tests the initial state of a ModifierButtons object.
+    btns = ModifierButtons()
+    assert btns == ModifierButtons(btns)
+    assert btns != ModifierButtons()
+    assert btns.matches(ModifierButtons())
+    assert not btns.is_down("alt")
+    assert not btns.is_any_down()
+    assert not btns.has_button("alt")
+    assert btns.get_prefix() == ""
+    assert btns.get_num_buttons() == 0
+    assert len(btns.buttons) == 0
+
+
+def test_modifierbuttons_cow():
+    # Tests the copy-on-write mechanism of the button list.
+    btns1 = ModifierButtons()
+    btns1.add_button("space")
+
+    # Modifying original should not affect copy
+    btns2 = ModifierButtons(btns1)
+    assert tuple(btns2.buttons) == tuple(btns1.buttons)
+    btns1.add_button("enter")
+    assert tuple(btns1.buttons) == ("space", "enter")
+    assert tuple(btns2.buttons) == ("space",)
+
+    # Modifying copy should not affect original
+    btns3 = ModifierButtons(btns2)
+    assert tuple(btns3.buttons) == tuple(btns2.buttons)
+    btns3.add_button("escape")
+    assert tuple(btns2.buttons) == ("space",)
+    assert tuple(btns3.buttons) == ("space", "escape")