Don't attempt to write until it is time.

4 files changed, 23 insertions, 4 deletions

diff --git a/ttystatus/messager.py b/ttystatus/messager.py
index 43fb0e1..c322590 100644
--- a/ttystatus/messager.py
+++ b/ttystatus/messager.py
@@ -85,14 +85,17 @@ class Messager(object):
             self._raw_write('\r' + (' ' * len(self._last_msg)) + '\r')
         self._raw_write(string)
         self._last_msg = string
+
+    def time_to_write(self):
+        '''Is it time to write now?'''
+        return self._now() - self._last_time >= self._period
             
     def write(self, string):
         '''Write raw data, but only once per period.'''
         string = string[:self.width]
-        now = self._now()
-        if now - self._last_time >= self._period:
+        if self.time_to_write():
             self._overwrite(string)
-            self._last_time = now
+            self._last_time = self._now()
         self._cached_msg = string
             
     def clear(self):
diff --git a/ttystatus/messager_tests.py b/ttystatus/messager_tests.py
index 4830727..b57fbaf 100644
--- a/ttystatus/messager_tests.py
+++ b/ttystatus/messager_tests.py
@@ -46,6 +46,18 @@ class MessagerTests(unittest.TestCase):
     def test_raw_writes_something_if_output_is_not_a_terminal(self):
         self.messager._raw_write('foo')
         self.assertEqual(self.output.getvalue(), 'foo')
+
+    def test_knows_it_is_time_to_write_at_start(self):
+        self.assert_(self.messager.time_to_write())
+
+    def test_knows_it_is_not_time_to_write_right_after_previous_one(self):
+        self.messager._last_time = self.messager._now()
+        self.assertFalse(self.messager.time_to_write())
+
+    def test_knows_it_is_time_to_write_after_a_period(self):
+        self.messager._last_time = (self.messager._now() - 
+                                    self.messager._period*2)
+        self.assert_(self.messager.time_to_write())
         
     def test_cached_write_writes_first_thing(self):
         self.messager.write('foo')
diff --git a/ttystatus/status.py b/ttystatus/status.py
index d7d8ef4..67443fc 100644
--- a/ttystatus/status.py
+++ b/ttystatus/status.py
@@ -62,7 +62,8 @@ class TerminalStatus(object):
         for w in self._interests.get(key, []):
             w.update(self, width)
             width -= len(str(w))
-        self._m.write(''.join(str(w) for w in self._widgets))
+        if self._m.time_to_write():
+            self._m.write(''.join(str(w) for w in self._widgets))
     
     def increase(self, key, delta):
         '''Increase value for a key by a given amount.'''
diff --git a/ttystatus/status_tests.py b/ttystatus/status_tests.py
index 36bc4bd..d22db53 100644
--- a/ttystatus/status_tests.py
+++ b/ttystatus/status_tests.py
@@ -25,6 +25,9 @@ class DummyMessager(object):
 
     def clear(self):
         pass
+
+    def time_to_write(self):
+        return True
         
     def write(self, string):
         pass