1 files changed, 66 insertions, 0 deletions
diff --git a/storage/test/unit/test_levenshtein.js b/storage/test/unit/test_levenshtein.js
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+++ b/storage/test/unit/test_levenshtein.js
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+/* 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 = Services.storage.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");
+  Assert.ok(stmt.executeStep());
+  let enc = stmt.getString(0);
+  stmt.finalize();
+
+  // The value returned will actually be UTF-16le or UTF-16be.
+  Assert.ok(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 {
+    Assert.ok(stmt.executeStep());
+    Assert.equal(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());
+}