diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 17d2b7945..91b7f072b 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -163,7 +163,7 @@ test1516 test1517 \
 test1520 \
 \
 test1525 test1526 test1527 test1528 test1529 test1530 test1531 test1532 \
-test1533 test1534 test1535 test1536 \
+test1533 test1534 test1535 test1536 test1537 \
 test1540 test1541 \
 \
 test1600 test1601 test1602 test1603 test1604 test1605 test1606 \
diff --git a/tests/data/test1537 b/tests/data/test1537
new file mode 100644
index 000000000..33d8ab3d9
--- /dev/null
+++ b/tests/data/test1537
@@ -0,0 +1,45 @@
+<testcase>
+<info>
+<keywords>
+URL escape
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+</reply>
+
+# Client-side
+<client>
+<server>
+none
+</server>
+<tool>
+lib1537
+</tool>
+
+<name>
+libcurl URL escape/unescape tests
+</name>
+<command>
+nothing
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<stdout>
+%2F%3A%3B%3C%3D%3E%3F%91%A2%B3%C4%D5%E6%F7
+%2F%3A%3B%3C%3D%3E%3F%91%A2%B3%C4%D5%E6%F7
+outlen == 14
+unescape == original? YES
+[old] outlen == 14
+[old] unescape == original? YES
+escape -1 length: (nil)
+unescape -1 length: (nil) 2017
+</stdout>
+</verify>
+
+</testcase>
diff --git a/tests/libtest/Makefile.inc b/tests/libtest/Makefile.inc
index d344a1218..70e2cc2fd 100644
--- a/tests/libtest/Makefile.inc
+++ b/tests/libtest/Makefile.inc
@@ -24,7 +24,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect                \
  lib1509 lib1510 lib1511 lib1512 lib1513 lib1514 lib1515         lib1517 \
  lib1520 \
  lib1525 lib1526 lib1527 lib1528 lib1529 lib1530 lib1531 lib1532 lib1533 \
- lib1534 lib1535 lib1536 \
+ lib1534 lib1535 lib1536 lib1537 \
  lib1540 lib1541 \
  lib1900 \
  lib2033
@@ -416,6 +416,10 @@ lib1536_SOURCES = lib1536.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1536_LDADD = $(TESTUTIL_LIBS)
 lib1536_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1536
 
+lib1537_SOURCES = lib1537.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1537_LDADD = $(TESTUTIL_LIBS)
+lib1537_CPPFLAGS = $(AM_CPPFLAGS)
+
 lib1540_SOURCES = lib1540.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1540_LDADD = $(TESTUTIL_LIBS)
 lib1540_CPPFLAGS = $(AM_CPPFLAGS)
diff --git a/tests/libtest/lib1537.c b/tests/libtest/lib1537.c
new file mode 100644
index 000000000..d449164e4
--- /dev/null
+++ b/tests/libtest/lib1537.c
@@ -0,0 +1,83 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "test.h"
+
+#include "memdebug.h"
+
+int test(char *URL)
+{
+  unsigned char a[] = {0x2f, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+                       0x91, 0xa2, 0xb3, 0xc4, 0xd5, 0xe6, 0xf7};
+  CURLcode res = CURLE_OK;
+  char *ptr = NULL;
+  int asize;
+  int outlen;
+  char *raw;
+
+  (void)URL; /* we don't use this */
+
+  if(curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK) {
+    fprintf(stderr, "curl_global_init() failed\n");
+    return TEST_ERR_MAJOR_BAD;
+  }
+
+  asize = (int)sizeof(a);
+  ptr = curl_easy_escape(NULL, (char *)a, asize);
+  printf("%s\n", ptr);
+  if(ptr)
+    curl_free(ptr);
+
+  /* deprecated API */
+  ptr = curl_escape((char *)a, asize);
+  printf("%s\n", ptr);
+
+  raw = curl_easy_unescape(NULL, ptr, (int)strlen(ptr), &outlen);
+  printf("outlen == %d\n", outlen);
+  printf("unescape == original? %s\n",
+         memcmp(raw, a, outlen) ? "no" : "YES");
+  if(raw)
+    curl_free(raw);
+
+  /* deprecated API */
+  raw = curl_unescape(ptr, (int)strlen(ptr));
+  outlen = (int)strlen(raw);
+  printf("[old] outlen == %d\n", outlen);
+  printf("[old] unescape == original? %s\n",
+         memcmp(raw, a, outlen) ? "no" : "YES");
+  if(raw)
+    curl_free(raw);
+  if(ptr)
+    curl_free(ptr);
+
+  /* weird input length */
+  ptr = curl_easy_escape(NULL, (char *)a, -1);
+  printf("escape -1 length: %s\n", ptr);
+
+  /* weird input length */
+  outlen = 2017; /* just a value */
+  ptr = curl_easy_unescape(NULL, (char *)"moahahaha", -1, &outlen);
+  printf("unescape -1 length: %s %d\n", ptr, outlen);
+
+  curl_global_cleanup();
+
+  return (int)res;
+}