db: Add a function so Decades can list their Years

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

db/decade.py

@@ -7,6 +7,7 @@
 from gi.repository import GObject
 from . import execute
 from . import objects
+from . import year
 
 class Decade(objects.Row):
     def __gt__(self, rhs): return self.decade > rhs.decade
@@ -17,6 +18,11 @@ class Decade(objects.Row):
         return execute(f"SELECT {column} FROM decades "
                         "WHERE decadeid=?", [ self.rowid ])
 
+    def years(self):
+        cursor = execute(f"SELECT yearid FROM years "
+                          "WHERE decadeid=?", [ self.rowid ])
+        return [ year.Year(row["yearid"]) for row in cursor.fetchall() ]
+
     @GObject.Property
     def decade(self):
         return self.get_column("decade")

db/test_decade.py

@@ -49,3 +49,9 @@ class TestDecadeTable(unittest.TestCase):
 
         self.assertFalse(d2010 > d2020)
         self.assertFalse(d2020 < d2010)
+
+    def test_decade_years(self):
+        decade = db.decade.Table.insert(2020)
+        y2020 = db.year.Table.insert(2020)
+        y2021 = db.year.Table.insert(2021)
+        self.assertEqual(decade.years(), [ y2020, y2021 ])