Add no new logging handlers when reloading the module.

User @epogrebnyak found the bug. Fixes #11. Closes #27.

handout/__init__.py

@@ -8,6 +8,7 @@
 logger = logging.getLogger('handout')
 logger.setLevel(logging.INFO)
 logger.propagate = False  # Global logger should not print messages again.
-handler = logging.StreamHandler(sys.stdout)
-handler.setFormatter(logging.Formatter('%(message)s'))
-logger.addHandler(handler)
+if not logger.handlers:  # Reloading the module should not add another handler.
+  handler = logging.StreamHandler(sys.stdout)
+  handler.setFormatter(logging.Formatter('%(message)s'))
+  logger.addHandler(handler)

handout/handout.py

@@ -16,6 +16,9 @@ def __init__(self, directory, title='Handout'):
     self._title = title
     self._blocks = collections.defaultdict(list)
     self._pending = []
+    # The logger is configured in handout/__init__.py to make it available
+    # right after importing the handout package. This allows the user to change
+    # the logging level, message format, etc.
     self._logger = logging.getLogger('handout')
     for info in inspect.stack():
       if info.filename == __file__:

handout/tests/test_handout.py

@@ -1,5 +1,7 @@
 import handout
 
+
 def test_handout_on_title_arg_inserts_title(tmp_path):
-    output = handout.Handout(directory=tmp_path, title='This string')._generate(source='')   
-    assert '<title>This string</title>' in output
+    doc = handout.Handout(directory=tmp_path, title='This string')
+    output = doc._generate(source='')
+    assert '<title>This string</title>' in output