fix search history appending blank lines

babi.py

@@ -227,8 +227,10 @@ class Status:
             yield
         finally:
             for k, v in self._history.items():
-                with open(os.path.join(history_dir, k), 'a+') as f:
-                    f.write('\n'.join(v[self._history_orig_len[k]:]) + '\n')
+                new_history = v[self._history_orig_len[k]:]
+                if new_history:
+                    with open(os.path.join(history_dir, k), 'a+') as f:
+                        f.write('\n'.join(new_history) + '\n')
 
     def update(self, status: str) -> None:
         self._status = status

tests/search_test.py

@@ -296,3 +296,13 @@ def test_search_reverse_search_keeps_current_text_displayed():
         h.press('^R')
         h.await_text('search(reverse-search)``: ohai')
         h.press('^C')
+
+
+def test_search_history_extra_blank_lines(xdg_data_home):
+    with run() as h, and_exit(h):
+        h.press('^W')
+        h.press_and_enter('hello')
+    with run() as h, and_exit(h):
+        pass
+    contents = xdg_data_home.join('babi/history/search').read()
+    assert contents == 'hello\n'