1 files changed, 30 insertions, 0 deletions
diff --git a/unit-tests/cmd-errors.mk b/unit-tests/cmd-errors.mk
new file mode 100644
index 000000000000..5ad4be311873
--- /dev/null
+++ b/unit-tests/cmd-errors.mk
@@ -0,0 +1,30 @@
+# $NetBSD: cmd-errors.mk,v 1.3 2020/11/09 23:36:34 rillig Exp $
+#
+# Demonstrate how errors in variable expansions affect whether the commands
+# are actually executed.
+
+all: undefined unclosed-variable unclosed-modifier unknown-modifier end
+
+# Undefined variables are not an error.  They expand to empty strings.
+undefined:
+	: $@ ${UNDEFINED} eol
+
+# XXX: As of 2020-11-01, this command is executed even though it contains
+# parse errors.
+unclosed-variable:
+	: $@ ${UNCLOSED
+
+# XXX: As of 2020-11-01, this command is executed even though it contains
+# parse errors.
+unclosed-modifier:
+	: $@ ${UNCLOSED:
+
+# XXX: As of 2020-11-01, this command is executed even though it contains
+# parse errors.
+unknown-modifier:
+	: $@ ${UNKNOWN:Z} eol
+
+end:
+	: $@ eol
+
+# XXX: As of 2020-11-02, despite the parse errors, the exit status is 0.