audio: Create custom PreviousButton and NextButton buttons

Along with a shared base class for these buttons, and soon the
PlayPause button

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

audio/controls.py

@@ -2,6 +2,31 @@
 from . import menu
 from gi.repository import Gtk, Gst
 
+
+class ControlButton(Gtk.Button):
+    def __init__(self, player, icon):
+        Gtk.Button.__init__(self)
+        self.add_css_class("large-icons")
+        self.set_icon_name(icon)
+        self.player = player
+
+
+class PreviousButton(ControlButton):
+    def __init__(self, player):
+        ControlButton.__init__(self, player, "media-skip-backward")
+
+    def do_clicked(self):
+        self.player.previous()
+
+
+class NextButton(ControlButton):
+    def __init__(self, player):
+        ControlButton.__init__(self, player, "media-skip-forward")
+
+    def do_clicked(self):
+        self.player.next()
+
+
 class Controls(Gtk.Box):
     def __init__(self):
         Gtk.Box.__init__(self)

audio/test_controls.py

@@ -1,10 +1,51 @@
 # Copyright 2021 (c) Anna Schumaker.
-from . import controls
-from lib import settings
-from gi.repository import Gtk, Gst, GLib
 import unittest
+from gi.repository import GObject
+from gi.repository import Gtk
+from gi.repository import Gst
+from . import controls
+
+class FakePlayer(GObject.GObject):
+    def __init__(self):
+        GObject.GObject.__init__(self)
+        self.prev = False
+        self.nxt = False
+
+    def previous(self): self.prev = True
+    def next(self): self.nxt = True
+
+
+class TestControlButton(unittest.TestCase):
+    def test_control_button(self):
+        fake = FakePlayer()
+        ctrl = controls.ControlButton(fake, "missing-icon")
+        self.assertIsInstance(ctrl, Gtk.Button)
+        self.assertTrue(ctrl.has_css_class("large-icons"))
+        self.assertEqual(ctrl.get_icon_name(), "missing-icon")
+        self.assertEqual(ctrl.player, fake)
+
+
+class TestPreviousButton(unittest.TestCase):
+    def test_previous_button(self):
+        fake = FakePlayer()
+        prev = controls.PreviousButton(fake)
+
+        self.assertIsInstance(prev, controls.ControlButton)
+        self.assertEqual(prev.get_icon_name(), "media-skip-backward")
+        prev.emit("clicked")
+        self.assertTrue(fake.prev)
+
+
+class TestNextButton(unittest.TestCase):
+    def test_next_button(self):
+        fake = FakePlayer()
+        next = controls.NextButton(fake)
+
+        self.assertIsInstance(next, controls.ControlButton)
+        self.assertEqual(next.get_icon_name(), "media-skip-forward")
+        next.emit("clicked")
+        self.assertTrue(fake.nxt)
 
-main_context = GLib.main_context_default()
 
 class TestControls(unittest.TestCase):
     def test_controls_init(self):