diff --git a/tests/codes.test b/tests/codes.test
new file mode 100644
index 000000000..c1e144651
--- /dev/null
+++ b/tests/codes.test
@@ -0,0 +1,37 @@
+# codes command
+
+<
+1/1 (123)
+ (a)  1
+
+1/1 ()
+ (a)  1
+
+1/1
+ (a)  1
+
+1/1 (124)
+ (a)  1
+
+1/1 (123)
+ (a)  1
+
+1/1
+ (a)  1
+
+# 1. Show non-empty codes by default, in parse order, including duplicates.
+$ hledger -f - codes
+123
+124
+123
+>=
+
+# 2. With -E, also show empty/missing codes as blank lines.
+$ hledger -f - codes -E
+123
+
+
+124
+123
+
+>=