header: Add a custom Header class

The header currently contains just the title & subtitle information, but
will be expanded to add volume controls in the next patch.

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

emmental/__init__.py

@@ -2,6 +2,7 @@
 """Set up our Application."""
 from . import gsetup
 from . import db
+from . import header
 from . import mpris2
 from . import options
 from . import window
@@ -27,9 +28,15 @@ class Application(Adw.Application):
                          resource_base_path=gsetup.RESOURCE_PATH)
         self.add_main_option_entries([options.Version])
 
+    def build_header(self) -> header.Header:
+        """Build a new header instance."""
+        return header.Header(sql=self.db, title=VERSION_STRING)
+
     def build_window(self) -> window.Window:
         """Build a new window instance."""
-        win = window.Window(VERSION_STRING)
+        win = window.Window(VERSION_STRING,
+                            header=self.build_header())
+
         for (setting, property) in [("window.width", "default-width"),
                                     ("window.height", "default-height")]:
             self.db.settings.bind_setting(setting, win, property)

emmental/header/__init__.py

@@ -0,0 +1,26 @@
+# Copyright 2022 (c) Anna Schumaker.
+"""A custom Gtk.HeaderBar configured for our application."""
+from gi.repository import GObject
+from gi.repository import Gtk
+from gi.repository import Adw
+from .. import db
+
+SUBTITLE = "The Cheesy Music Player"
+
+
+class Header(Gtk.HeaderBar):
+    """Our custom Gtk.HeaderBar containing window title and volume controls."""
+
+    sql = GObject.Property(type=db.Connection)
+    title = GObject.Property(type=str)
+    subtitle = GObject.Property(type=str)
+
+    def __init__(self, sql: db.Connection, title: str):
+        """Initialize the HeaderBar."""
+        super().__init__(title=title, subtitle=SUBTITLE, sql=sql)
+        self._title = Adw.WindowTitle(title=self.title, subtitle=self.subtitle)
+
+        self.bind_property("title", self._title, "title")
+        self.bind_property("subtitle", self._title, "subtitle")
+
+        self.set_title_widget(self._title)

tests/header/test_header.py

@@ -0,0 +1,32 @@
+# Copyright 2022 (c) Anna Schumaker.
+"""Tests our application header."""
+import emmental
+import tests.util
+from gi.repository import Gtk
+from gi.repository import Adw
+
+
+class TestHeader(tests.util.TestCase):
+    """Test case for our custom Gtk.HeaderBar."""
+
+    def setUp(self):
+        """Set up common variables."""
+        super().setUp()
+        self.header = emmental.header.Header(sql=self.sql, title="Test Title")
+
+    def test_constants(self):
+        """Check that constants are set correctly."""
+        self.assertEqual(emmental.header.SUBTITLE, "The Cheesy Music Player")
+
+    def test_title(self):
+        """Check that the title is set correctly."""
+        self.assertIsInstance(self.header, Gtk.HeaderBar)
+        self.assertIsInstance(self.header._title, Adw.WindowTitle)
+
+        self.assertEqual(self.header.get_title_widget(), self.header._title)
+        self.assertEqual(self.header.title, "Test Title")
+        self.assertEqual(self.header._title.get_title(), "Test Title")
+
+        self.assertEqual(self.header.subtitle, emmental.header.SUBTITLE)
+        self.assertEqual(self.header._title.get_subtitle(),
+                         emmental.header.SUBTITLE)

tests/test_emmental.py

@@ -86,3 +86,5 @@ class TestEmmental(unittest.TestCase):
         win = self.application.build_window()
 
         self.assertIsInstance(win, emmental.window.Window)
+        self.assertIsInstance(win.header, emmental.header.Header)
+        self.assertEqual(win.header.title, emmental.VERSION_STRING)