diff --git a/sshfs.c b/sshfs.c
index 4cdf1223..0682be9a 100644
--- a/sshfs.c
+++ b/sshfs.c
@@ -1322,7 +1322,7 @@ static int connect_to(struct conn *conn, char *host, char *port)
 	return 0;
 }
 
-static int connect_vsock(struct conn *conn, char *vsock)
+static int connect_vsock(struct conn *conn, const char *vsock)
 {
 #ifndef __linux__
 	fprintf(stderr, "vsock is not available\n");
@@ -1333,14 +1333,13 @@ static int connect_vsock(struct conn *conn, char *vsock)
 	struct sockaddr_vm addr;
 	unsigned int cid;
 	unsigned int port;
-	char *delim;
+	const char *delim;
 
 	delim = strchr(vsock, ':');
 	if (delim == NULL) {
 		fprintf(stderr, "invalid vsock, expecting CID:PORT\n");
 		return -1;
 	}
-	*delim = '\0';
 	errno = 0;
 	cid = strtoul(vsock, NULL, 10);
 	if (errno) {
diff --git a/test/meson.build b/test/meson.build
index 18ac05ee..9e8934f5 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -19,6 +19,15 @@ test_cache = executable('test_cache', 'test_cache.c',
                         install: false)
 test('cache', test_cache, suite: 'unit')
 
+if host_machine.system() == 'linux'
+  test_vsock = executable('test_vsock', ['test_vsock.c', '../cache.c'],
+                          include_directories: include_dirs,
+                          dependencies: sshfs_deps,
+                          c_args: ['-DFUSE_USE_VERSION=31'],
+                          install: false)
+  test('vsock', test_vsock, suite: 'unit')
+endif
+
 # Provide something helpful when running 'ninja test'
 wrong_cmd = executable('wrong_command', 'wrong_command.c',
                        install: false)
diff --git a/test/test_vsock.c b/test/test_vsock.c
new file mode 100644
index 00000000..7c72ba75
--- /dev/null
+++ b/test/test_vsock.c
@@ -0,0 +1,106 @@
+/* Exercise the real connection helper without a VSOCK device or FUSE mount. */
+#define _GNU_SOURCE
+#include <sys/socket.h>
+#include <unistd.h>
+
+static int test_socket(int domain, int type, int protocol);
+static int test_connect(int fd, const struct sockaddr *addr, socklen_t len);
+static int test_close(int fd);
+int sshfs_main(int argc, char *argv[]);
+
+#define socket test_socket
+#define connect test_connect
+#define close test_close
+#define main sshfs_main
+#include "../sshfs.c"
+#undef main
+#undef close
+#undef connect
+#undef socket
+
+#define TEST_FD 42
+
+enum failure {
+	NO_FAILURE,
+	SOCKET_FAILURE,
+	CONNECT_FAILURE,
+};
+
+static enum failure failure;
+static int socket_calls;
+static int connect_calls;
+static int close_calls;
+
+static int test_socket(int domain, int type, int protocol)
+{
+	g_assert_cmpint(domain, ==, AF_VSOCK);
+	g_assert_cmpint(type, ==, SOCK_STREAM);
+	g_assert_cmpint(protocol, ==, 0);
+	socket_calls++;
+	if (failure == SOCKET_FAILURE && socket_calls == 1) {
+		errno = EAFNOSUPPORT;
+		return -1;
+	}
+	return TEST_FD;
+}
+
+static int test_connect(int fd, const struct sockaddr *addr, socklen_t len)
+{
+	const struct sockaddr_vm *vm = (const struct sockaddr_vm *) addr;
+
+	g_assert_cmpint(fd, ==, TEST_FD);
+	g_assert_cmpuint(len, ==, sizeof(*vm));
+	g_assert_cmpint(vm->svm_family, ==, AF_VSOCK);
+	g_assert_cmpuint(vm->svm_cid, ==, 3);
+	g_assert_cmpuint(vm->svm_port, ==, 12345);
+	connect_calls++;
+	if (failure == CONNECT_FAILURE && connect_calls == 1) {
+		errno = ECONNREFUSED;
+		return -1;
+	}
+	return 0;
+}
+
+static int test_close(int fd)
+{
+	g_assert_cmpint(fd, ==, TEST_FD);
+	close_calls++;
+	return 0;
+}
+
+static void test_reuse_address(gconstpointer data)
+{
+	char address[] = "3:12345";
+	struct conn first = { .rfd = -1, .wfd = -1 };
+	struct conn second = { .rfd = -1, .wfd = -1 };
+	int first_result;
+	int second_result;
+
+	failure = GPOINTER_TO_INT(data);
+	socket_calls = connect_calls = close_calls = 0;
+	first_result = connect_vsock(&first, address);
+	second_result = connect_vsock(&second, address);
+
+	g_assert_cmpint(first_result, ==, failure == NO_FAILURE ? 0 : -1);
+	g_assert_cmpint(second_result, ==, 0);
+	g_assert_cmpstr(address, ==, "3:12345");
+	g_assert_cmpint(first.rfd, ==, failure == NO_FAILURE ? TEST_FD : -1);
+	g_assert_cmpint(first.wfd, ==, first.rfd);
+	g_assert_cmpint(second.rfd, ==, TEST_FD);
+	g_assert_cmpint(second.wfd, ==, TEST_FD);
+	g_assert_cmpint(socket_calls, ==, 2);
+	g_assert_cmpint(connect_calls, ==, failure == SOCKET_FAILURE ? 1 : 2);
+	g_assert_cmpint(close_calls, ==, failure == CONNECT_FAILURE ? 1 : 0);
+}
+
+int main(int argc, char *argv[])
+{
+	g_test_init(&argc, &argv, NULL);
+	g_test_add_data_func("/vsock/reuse-after-success",
+			     GINT_TO_POINTER(NO_FAILURE), test_reuse_address);
+	g_test_add_data_func("/vsock/retry-after-socket-failure",
+			     GINT_TO_POINTER(SOCKET_FAILURE), test_reuse_address);
+	g_test_add_data_func("/vsock/retry-after-connect-failure",
+			     GINT_TO_POINTER(CONNECT_FAILURE), test_reuse_address);
+	return g_test_run();
+}