test1918: verify curl_easy_option_by_name() and curl_easy_option_by_id()

... and as a practical side-effect, make sure that the
Curl_easyopts_check() function is asserted in debug builds, which we
want to detect mismatches between the options list in easyoptions.c and
the options in curl.h

Found-by: Gisle Vanem
Bug: https://github.com/curl/curl/commit/08e8455dddc5e48e58a12ade3815c01ae3da3b64#commitcomment-45991815

Closes #6461

tests/data/Makefile.inc

@@ -207,7 +207,9 @@ test1800 test1801 \
 \
                                     test1904 test1905 test1906 test1907 \
 test1908 test1909 test1910 test1911 test1912 test1913 test1914 test1915 \
-test1916 test1917 test1933 \
+test1916 test1917 test1918 \
+\
+test1933 \
 \
 test2000 test2001 test2002 test2003 test2004 test2005 test2006 test2007 \
 test2008 test2009 test2010 test2011 test2012 test2013 test2014 test2015 \

tests/data/test1918

@@ -0,0 +1,33 @@
+<testcase>
+<info>
+<keywords>
+curl_easy_option
+curl_easy_option_by_name
+curl_easy_option_by_id
+</keywords>
+</info>
+
+# Server-side
+<reply>
+</reply>
+
+# Client-side
+<client>
+<server>
+none
+</server>
+<name>
+curl_easy_option_by_name() and curl_easy_option_by_id()
+</name>
+<tool>
+lib1918
+</tool>
+
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<stdout>
+</stdout>
+</verify>
+</testcase>

tests/libtest/Makefile.inc

@@ -60,7 +60,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect                \
  lib1558 lib1559 lib1560 lib1564 lib1565 lib1567 lib1568 \
  lib1591 lib1592 lib1593 lib1594 lib1596 \
          lib1905 lib1906 lib1907 lib1908 lib1910 lib1911 lib1912 lib1913 \
-         lib1915 lib1916 lib1917 lib1933 \
+         lib1915 lib1916 lib1917 lib1918 lib1933 \
          lib3010
 
 chkdecimalpoint_SOURCES = chkdecimalpoint.c ../../lib/mprintf.c \
@@ -668,6 +668,9 @@ lib1916_CPPFLAGS = $(AM_CPPFLAGS)
 lib1917_SOURCES = lib1916.c $(SUPPORTFILES) $(WARNLESS)
 lib1917_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1917
 
+lib1918_SOURCES = lib1918.c $(SUPPORTFILES) $(WARNLESS)
+lib1918_CPPFLAGS = $(AM_CPPFLAGS)
+
 lib1933_SOURCES = lib1933.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1933_LDADD = $(TESTUTIL_LIBS)
 lib1933_CPPFLAGS = $(AM_CPPFLAGS)

tests/libtest/lib1918.c

@@ -0,0 +1,55 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2021, 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.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 "testutil.h"
+#include "warnless.h"
+#include "memdebug.h"
+
+int test(char *URL)
+{
+  const struct curl_easyoption *o;
+  int error = 0;
+  (void)URL;
+
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  for(o = curl_easy_option_next(NULL);
+      o;
+      o = curl_easy_option_next(o)) {
+    const struct curl_easyoption *ename =
+      curl_easy_option_by_name(o->name);
+    const struct curl_easyoption *eid =
+      curl_easy_option_by_id(o->id);
+
+    if(ename->id != o->id) {
+      printf("name lookup id %d doesn't match %d\n",
+             ename->id, o->id);
+    }
+    else if(eid->id != o->id) {
+      printf("ID lookup %d doesn't match %d\n",
+             ename->id, o->id);
+    }
+  }
+  curl_global_cleanup();
+  return error;
+}