Add tests for the example fts3 "rank" function that appears in the

documentation.

FossilOrigin-Name: 702b137aa4f76543647e177beeb1ca2b3cd18c61021c78880e9aa8656f341d65

test/fts3rank.test

@@ -0,0 +1,64 @@
+# 2017 October 7
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#*************************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this script is testing the FTS3 module.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix fts3expr5
+
+# If SQLITE_ENABLE_FTS3 is defined, omit this file.
+ifcapable !fts3 {
+  finish_test
+  return
+}
+
+install_fts3_rank_function db
+do_execsql_test 1.0 {
+  CREATE VIRTUAL TABLE t1 USING fts3(a, b);
+  INSERT INTO t1 VALUES('one two', 'one');
+  INSERT INTO t1 VALUES('one two', 'three');
+  INSERT INTO t1 VALUES('one two', 'two');
+}
+
+do_execsql_test 1.1 {
+  SELECT * FROM t1 WHERE t1 MATCH 'one' 
+  ORDER BY rank(matchinfo(t1), 1.0, 1.0) DESC, rowid
+} {
+  {one two} one
+  {one two} three
+  {one two} two
+}
+
+do_execsql_test 1.2 {
+  SELECT * FROM t1 WHERE t1 MATCH 'two' 
+  ORDER BY rank(matchinfo(t1), 1.0, 1.0) DESC, rowid
+} {
+  {one two} two
+  {one two} one
+  {one two} three
+}
+
+do_catchsql_test 1.3 {
+  SELECT * FROM t1 ORDER BY rank(matchinfo(t1), 1.0, 1.0) DESC, rowid
+} {1 {invalid matchinfo blob passed to function rank()}}
+
+do_catchsql_test 1.4 {
+  SELECT * FROM t1 ORDER BY rank(x'0000000000000000') DESC, rowid
+} {0 {{one two} one {one two} three {one two} two}}
+
+do_catchsql_test 1.5 {
+  SELECT * FROM t1 ORDER BY rank(x'0100000001000000') DESC, rowid
+} {1 {invalid matchinfo blob passed to function rank()}}
+
+finish_test
+