gecko-dev/storage/test/unit/test_levenshtein.js
2012-05-21 12:12:37 +01:00

76 lines
2.2 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// This file tests the Levenshtein Distance function we've registered.
function createUtf16Database()
{
print("Creating the in-memory UTF-16-encoded database.");
let conn = getService().openSpecialDatabase("memory");
conn.executeSimpleSQL("PRAGMA encoding = 'UTF-16'");
print("Make sure the encoding was set correctly and is now UTF-16.");
let stmt = conn.createStatement("PRAGMA encoding");
do_check_true(stmt.executeStep());
let enc = stmt.getString(0);
stmt.finalize();
// The value returned will actually be UTF-16le or UTF-16be.
do_check_true(enc === "UTF-16le" || enc === "UTF-16be");
return conn;
}
function check_levenshtein(db, s, t, expectedDistance)
{
var stmt = db.createStatement("SELECT levenshteinDistance(:s, :t) AS result");
stmt.params.s = s;
stmt.params.t = t;
try {
do_check_true(stmt.executeStep());
do_check_eq(expectedDistance, stmt.row.result);
}
finally {
stmt.reset();
stmt.finalize();
}
}
function testLevenshtein(db)
{
// Basic tests.
check_levenshtein(db, "", "", 0);
check_levenshtein(db, "foo", "", 3);
check_levenshtein(db, "", "bar", 3);
check_levenshtein(db, "yellow", "hello", 2);
check_levenshtein(db, "gumbo", "gambol", 2);
check_levenshtein(db, "kitten", "sitten", 1);
check_levenshtein(db, "sitten", "sittin", 1);
check_levenshtein(db, "sittin", "sitting", 1);
check_levenshtein(db, "kitten", "sitting", 3);
check_levenshtein(db, "Saturday", "Sunday", 3);
check_levenshtein(db, "YHCQPGK", "LAHYQQKPGKA", 6);
// Test SQL NULL handling.
check_levenshtein(db, "foo", null, null);
check_levenshtein(db, null, "bar", null);
check_levenshtein(db, null, null, null);
// The levenshteinDistance function allocates temporary memory on the stack
// if it can. Test some strings long enough to force a heap allocation.
var dots1000 = Array(1001).join(".");
var dashes1000 = Array(1001).join("-");
check_levenshtein(db, dots1000, dashes1000, 1000);
}
function run_test()
{
testLevenshtein(getOpenedDatabase());
testLevenshtein(createUtf16Database());
}