test line chooser sticky

src/test_writer.py

@@ -0,0 +1,36 @@
+import unittest
+
+import writer
+
+class TestLineChooser(unittest.TestCase):
+   def test_latest_sticky(self):
+      stale_something = self.new_line(False, 1, 1)
+      stale_nothing = self.new_line(False, 1, None)
+      old_something = self.new_line(True, 2, 2)
+      old_nothing = self.new_line(True, 2, None)
+      new_something = self.new_line(True, 3, 3)
+      new_nothing = self.new_line(True, 3, None)
+
+      chooser = writer.LineChooserLatestSticky()
+
+      for name, c in ({
+         "nothing over stale":         [new_nothing, stale_something],
+         "slightly old over nothing":  [old_something, new_nothing],
+         "new and nonzero":            [new_something, old_something],
+         "new over nothing":           [new_something, old_nothing],
+         "new over stale nothing":     [new_something, stale_nothing],
+      }).items():
+         self.assertEqual(
+            c[0],
+            chooser.choose(c[0], c[1]),
+            name,
+         )
+
+   def new_line(self, is_recent, t, v):
+      result = writer.Line(v)
+      result.t = t
+      result.is_recent = lambda *args: is_recent
+      return result
+
+if __name__ == "__main__":
+   unittest.main()

src/writer.py

@@ -78,10 +78,10 @@ class Line:
       return not self.v
 
    def is_recent(self):
-      return time.time() - self.t < 1
+      return time.time() - self.t < 5
 
 class LineChooser:
-   def choose(a, b):
+   def choose(self, a, b):
       if not a:
          return b
       if not b: