1 files changed, 51 insertions, 0 deletions
diff --git a/lib/ccan/failtest/test/run-write.c b/lib/ccan/failtest/test/run-write.c
new file mode 100644
index 0000000000..6a712fec53
--- /dev/null
+++ b/lib/ccan/failtest/test/run-write.c
@@ -0,0 +1,51 @@
+/* Include the C files directly. */
+#include <ccan/failtest/failtest.c>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <assert.h>
+#include <ccan/tap/tap.h>
+
+int main(int argc, char *argv[])
+{
+	int fd;
+	char *p;
+	char buf[] = "Hello world!";
+
+	plan_tests(5);
+	failtest_init(argc, argv);
+
+	fd = failtest_open("run-write-scratchpad", __FILE__, __LINE__,
+			   O_RDWR|O_CREAT, 0600);
+	/* Child will fail, ignore. */
+	if (fd < 0)
+		failtest_exit(0);
+	if (write(fd, buf, strlen(buf)) != strlen(buf))
+		abort();
+	ok1(lseek(fd, 0, SEEK_CUR) == strlen(buf));
+
+	p = failtest_malloc(100, __FILE__, __LINE__);
+	if (!p) {
+		/* We are the child.  Do a heap of writes. */
+		unsigned int i;
+
+		for (i = 0; i < strlen(buf)+1; i++)
+			if (failtest_write(fd, "x", 1, __FILE__, __LINE__)
+			    == 1)
+				break;
+		failtest_close(fd, __FILE__, __LINE__);
+		failtest_exit(0);
+	}
+
+	/* Seek pointer should be left alone! */
+	ok1(lseek(fd, 0, SEEK_CUR) == strlen(buf));
+	/* Length should be restored. */
+	ok1(lseek(fd, 0, SEEK_END) == strlen(buf));
+	lseek(fd, 0, SEEK_SET);
+	ok1(read(fd, buf, strlen(buf)) == strlen("Hello world!"));
+	ok1(strcmp(buf, "Hello world!") == 0);
+	failtest_close(fd, __FILE__, __LINE__);
+
+	return exit_status();
+}