lib: Create a custom filter Popover

For displaying errors in the regex that the user has entered

Implements: Issue #4 (Create common filtering widgets)
Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

lib/filter.py

@@ -1,6 +1,7 @@
 # Copyright 2021 (c) Anna Schumaker.
 import re
 from gi.repository import Gtk
+from . import version
 
 class Regex(Gtk.Filter):
     def __init__(self):
@@ -24,10 +25,23 @@ class Regex(Gtk.Filter):
         self.changed(change)
 
 
+class Popover(Gtk.Popover):
+    def __init__(self):
+        Gtk.Popover.__init__(self)
+        self.set_child(Gtk.Label())
+        self.set_autohide(False)
+
+    def popup(self, text):
+        self.get_child().set_text(text)
+        if not version.TESTING:
+            super().popup()
+
+
 class Entry(Gtk.SearchEntry):
     def __init__(self, filter):
         Gtk.SearchEntry.__init__(self)
         self.filter = filter
+        self.popover = Popover()
 
         self.set_margin_top(5)
         self.set_margin_bottom(5)
@@ -36,10 +50,16 @@ class Entry(Gtk.SearchEntry):
 
         self.set_property("placeholder-text", "Type to filter")
         self.connect("search-changed", self.changed)
+        self.popover.set_parent(self)
+
+    def __del__(self):
+        self.popover.unparent()
 
     def changed(self, entry):
         try:
             self.filter.set_pattern(self.get_text())
             self.remove_css_class("warning")
-        except:
+            self.popover.popdown()
+        except re.error as e:
             self.add_css_class("warning")
+            self.popover.popup(str(e))

lib/test_filter.py

@@ -40,18 +40,33 @@ class TestRegex(unittest.TestCase):
         self.assertFalse(filter.search("cde"))
 
 
+class TestPopover(unittest.TestCase):
+    def test_init(self):
+        popover = lib.filter.Popover()
+        self.assertIsInstance(popover, Gtk.Popover)
+        self.assertIsInstance(popover.get_child(), Gtk.Label)
+        self.assertFalse(popover.get_autohide())
+
+    def test_popup(self):
+        popover = lib.filter.Popover()
+        popover.popup("test")
+        self.assertEqual(popover.get_child().get_text(), "test")
+
+
 class TestEntry(unittest.TestCase):
     def test_init(self):
         filter = lib.filter.Regex()
         entry = lib.filter.Entry(filter)
 
         self.assertIsInstance(entry, Gtk.SearchEntry)
+        self.assertIsInstance(entry.popover, lib.filter.Popover)
         self.assertEqual(entry.get_property("placeholder-text"), "Type to filter")
         self.assertEqual(entry.get_margin_top(), 5)
         self.assertEqual(entry.get_margin_bottom(), 5)
         self.assertEqual(entry.get_margin_start(), 5)
         self.assertEqual(entry.get_margin_end(), 5)
         self.assertEqual(entry.filter, filter)
+        self.assertEqual(entry.popover.get_parent(), entry)
 
     def test_changed(self):
         filter = lib.filter.Regex()