1 files changed, 100 insertions, 0 deletions
diff --git a/src/format.c b/src/format.c
index db903e3..f9d0ed4 100644
--- a/src/format.c
+++ b/src/format.c
@@ -321,3 +321,103 @@ fmt_pid (rp_window_elem *elem, struct sbuf *buf)
   else
     sbuf_concat (buf, "?");
 }
+
+#ifdef RUN_FORMAT_TEST
+
+#include <assert.h>
+#include <locale.h>
+
+void rtp_test_concat_width(void);
+
+int main(void)
+{
+  /* We need to set up locale information for multibyte functions to work
+     correctly. */
+  setlocale(LC_ALL, "");
+
+  rtp_test_concat_width();
+  return 0;
+}
+
+void rtp_test_concat_width(void)
+{
+  struct sbuf *buf = NULL;
+
+  /* Zero length string, no limit. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "", -1);
+  assert(strcmp(sbuf_get(buf), "") == 0);
+  sbuf_free(buf);
+
+  /* Zero length string, non-zero limit. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "", 5);
+  assert(strcmp(sbuf_get(buf), "") == 0);
+  sbuf_free(buf);
+
+  /* ASCII string, no limit. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "hi there", -1);
+  assert(strcmp(sbuf_get(buf), "hi there") == 0);
+  concat_width(buf, " you", -1);
+  assert(strcmp(sbuf_get(buf), "hi there you") == 0);
+  sbuf_free(buf);
+
+  /* ASCII string, non-zero limit, truncated. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "hi there", 4);
+  assert(strcmp(sbuf_get(buf), "hi t") == 0);
+  sbuf_free(buf);
+
+  /* ASCII string, non-zero limit, not truncated. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "hi", 4);
+  assert(strcmp(sbuf_get(buf), "hi") == 0);
+  sbuf_free(buf);
+
+  /* UTF-8 string, no limit. */
+
+  buf = sbuf_new(0);
+  /* 0xe2 0x84 0xa2 is U+2122, the trademark symbol. */
+  concat_width(buf, "hi \xe2\x84\xa2 there", -1);
+  assert(strcmp(sbuf_get(buf), "hi \xe2\x84\xa2 there") == 0);
+  sbuf_free(buf);
+
+  /* UTF-8 string, non-zero limit, truncated at an okay spot counting either
+     by bytes or by characters. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "hi \xe2\x84\xa2 there you", 11);
+  assert(strcmp(sbuf_get(buf), "hi \xe2\x84\xa2 there ") == 0);
+  sbuf_free(buf);
+
+  /* UTF-8 string, non-zero limit, truncated such that if the limit were in
+     bytes that we would cut in the middle of a character. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "hi \xe2\x84\xa2 there you", 5);
+  assert(strcmp(sbuf_get(buf), "hi \xe2\x84\xa2 ") == 0);
+  sbuf_free(buf);
+
+  /* UTF-8 string, non-zero limit, not truncated. */
+
+  buf = sbuf_new(0);
+  concat_width(buf, "hi \xe2\x84\xa2 there you", 20);
+  assert(strcmp(sbuf_get(buf), "hi \xe2\x84\xa2 there you") == 0);
+  sbuf_free(buf);
+
+  /* Invalid character. */
+
+  buf = sbuf_new(0);
+  /* This is an invalid UTF-8 sequence. It's missing 0xa2. */
+  concat_width(buf, "hi \xe2\x84 there you", 20);
+  assert(strcmp(sbuf_get(buf), "hi ") == 0);
+  sbuf_free(buf);
+}
+
+#endif