1 files changed, 89 insertions, 0 deletions
diff --git a/regress/unittests/misc/test_xextendf.c b/regress/unittests/misc/test_xextendf.c
new file mode 100644
index 000000000000..3c1ee8b8b65c
--- /dev/null
+++ b/regress/unittests/misc/test_xextendf.c
@@ -0,0 +1,89 @@
+/* 	$OpenBSD: test_xextendf.c,v 1.1 2025/09/02 11:04:58 djm Exp $ */
+/*
+ * Regress test for misc xextendf() function.
+ *
+ * Placed in the public domain.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../test_helper/test_helper.h"
+
+#include "log.h"
+#include "misc.h"
+#include "xmalloc.h"
+
+void test_xextendf(void);
+
+void
+test_xextendf(void)
+{
+	char *s = NULL;
+
+	TEST_START("xextendf NULL string");
+	xextendf(&s, ",", "hello");
+	ASSERT_STRING_EQ(s, "hello");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+
+	TEST_START("xextendf empty string");
+	s = xstrdup("");
+	xextendf(&s, ",", "world");
+	ASSERT_STRING_EQ(s, "world");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+
+	TEST_START("xextendf append to string");
+	s = xstrdup("foo");
+	xextendf(&s, ",", "bar");
+	ASSERT_STRING_EQ(s, "foo,bar");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+
+	TEST_START("xextendf append with NULL separator");
+	s = xstrdup("foo");
+	xextendf(&s, NULL, "bar");
+	ASSERT_STRING_EQ(s, "foobar");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+
+	TEST_START("xextendf append with empty separator");
+	s = xstrdup("foo");
+	xextendf(&s, "", "bar");
+	ASSERT_STRING_EQ(s, "foobar");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+
+	TEST_START("xextendf with format string");
+	s = xstrdup("start");
+	xextendf(&s, ":", "s=%s,d=%d", "string", 123);
+	ASSERT_STRING_EQ(s, "start:s=string,d=123");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+
+	TEST_START("xextendf multiple appends");
+	s = NULL;
+	xextendf(&s, ",", "one");
+	ASSERT_STRING_EQ(s, "one");
+	xextendf(&s, ",", "two");
+	ASSERT_STRING_EQ(s, "one,two");
+	xextendf(&s, ":", "three=%d", 3);
+	ASSERT_STRING_EQ(s, "one,two:three=3");
+	xextendf(&s, NULL, "four");
+	ASSERT_STRING_EQ(s, "one,two:three=3four");
+	free(s);
+	s = NULL;
+	TEST_DONE();
+}