diff --git a/tests/test_reconcile.py b/tests/test_reconcile.py
index 90f8cf4..48ea3c3 100644
--- a/tests/test_reconcile.py
+++ b/tests/test_reconcile.py
@@ -1,3 +1,4 @@
+import argparse
 import datetime
 import decimal
 import io
@@ -12,6 +13,7 @@ from conservancy_beancount.reconcile.statement_reconciler import (
     format_output,
     match_statement_and_books,
     metadata_for_match,
+    parse_repo_relative_path,
     payee_match,
     read_amex_csv,
     read_fr_csv,
@@ -152,6 +154,13 @@ B4C = {
 }
 
 
+def test_warns_missing_env(monkeypatch):
+    monkeypatch.delenv('CONSERVANCY_REPOSITORY', raising=False)
+    with pytest.raises(argparse.ArgumentTypeError) as excinfo:
+        parse_repo_relative_path('/')  # path / always exists
+    assert "CONSERVANCY_REPOSITORY" in str(excinfo.value)
+
+
 def test_one_exact_match():
     statement = [S1]
     books = [B1]