Changed the app list string matching formula.

ui/app_list/search/tokenized_string_match_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/search/tokenized_string_match.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/strings/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace app_list {
 namespace test {
 
 // Returns a string of |text| marked the hits in |match| using block bracket.
-// e.g. text= "Text", hits = [{0,1}], returns "[T]ext".
+// e.g. text= "Text", match.hits = [{0,1}], returns "[T]ext".
 std::string MatchHit(const base::string16& text,
                      const TokenizedStringMatch& match) {
   base::string16 marked = text;
 
   const TokenizedStringMatch::Hits& hits = match.hits();
   for (TokenizedStringMatch::Hits::const_reverse_iterator it = hits.rbegin();
        it != hits.rend(); ++it) {
     const gfx::Range& hit = *it;
     marked.insert(hit.end(), 1, ']');
     marked.insert(hit.start(), 1, '[');
@@ skipping 84 matching lines @@
     EXPECT_TRUE(match_high.Calculate(
         base::UTF8ToUTF16(kTestCases[i].query_high), text));
     EXPECT_LT(match_low.relevance(), match_high.relevance())
         << "Test case " << i
         << " : text=" << kTestCases[i].text
         << ", query_low=" << kTestCases[i].query_low
         << ", query_high=" << kTestCases[i].query_high;
   }
 }
 
+// More specialized tests of the absolute relevance scores. (These tests are
+// minimal, because they are so brittle. Changing the scoring algorithm will
+// require updating this test.)
+TEST(TokenizedStringMatchTest, AbsoluteRelevance) {
+  const double kEpsilon = 0.006;
+  struct {
+    const char* text;
+    const char* query;
+    double expected_score;
+  } kTestCases[] = {
+      // The first few chars should increase the score extremely high. After
+      // that, they should count less.
+      // NOTE: 0.87 is a magic number, as it is the Omnibox score for a "pretty
+      // good" match. We want a 3-letter prefix match to be slightly above 0.87.
+      {"Google Chrome", "g", 0.5},
+      {"Google Chrome", "go", 0.75},
+      {"Google Chrome", "goo", 0.88},
+      {"Google Chrome", "goog", 0.94},
+  };
+
+  TokenizedStringMatch match;
+  for (size_t i = 0; i < arraysize(kTestCases); ++i) {
+    const base::string16 text(base::UTF8ToUTF16(kTestCases[i].text));
+    EXPECT_TRUE(match.Calculate(base::UTF8ToUTF16(kTestCases[i].query), text));
+    EXPECT_NEAR(match.relevance(), kTestCases[i].expected_score, kEpsilon)
+        << "Test case " << i << " : text=" << kTestCases[i].text
+        << ", query=" << kTestCases[i].query
+        << ", expected_score=" << kTestCases[i].expected_score;
+  }
+}
+
 }  // namespace test
 }  // namespace app_list