config: Make payment threshold configurable.

conservancy_beancount/config.py

@@ -157,7 +157,10 @@ class Config:
             return books.FiscalYear(month, day)
 
     def payment_threshold(self) -> decimal.Decimal:
-        return decimal.Decimal(0)
+        try:
+            return decimal.Decimal(self.file_config['Beancount']['payment threshold'])
+        except (KeyError, ValueError):
+            return decimal.Decimal(10)
 
     def repository_path(self) -> Optional[Path]:
         try:

tests/test_config.py

@@ -293,11 +293,22 @@ def test_relative_xdg_cache_home_ignored(tmp_path):
         cache_dir_path = config.cache_dir_path('TESTcache')
     assert cache_dir_path == tmp_path / '.cache/TESTcache'
 
-def test_payment_threshold():
+def test_default_payment_threshold():
     threshold = config_mod.Config().payment_threshold()
-    assert threshold == 0
     assert isinstance(threshold, (int, decimal.Decimal))
 
+@pytest.mark.parametrize('config_threshold', [
+    '15',
+    ' +15',
+    '15. ',
+    '15.0',
+    '15.00',
+])
+def test_payment_threshold(config_threshold):
+    config = config_mod.Config()
+    config.load_string(f'[Beancount]\npayment threshold = {config_threshold}\n')
+    assert config.payment_threshold() == decimal.Decimal(15)
+
 @pytest.mark.parametrize('config_path', [
     None,
     '',