[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

components/autofill/core/browser/autofill_manager_unittest.cc

Index: components/autofill/core/browser/autofill_manager_unittest.cc
diff --git a/components/autofill/core/browser/autofill_manager_unittest.cc b/components/autofill/core/browser/autofill_manager_unittest.cc
index 8778990ef781f579cee6028a5f533b66b8159ee0..a57700ac528f0eaac922e968165878f63510304d 100644
--- a/components/autofill/core/browser/autofill_manager_unittest.cc
+++ b/components/autofill/core/browser/autofill_manager_unittest.cc
@@ -3176,4 +3176,81 @@ TEST_F(AutofillManagerTest, GetCreditCardSuggestionsForNumberSpitAcrossFields) {
           "04/12", kVisaCard, autofill_manager_->GetPackedCreditCardID(4)));
 }
 
+// Test that suggestion tokens (substrings separated by characters from "
+// .,-_@") are matched against field contents.
+TEST_F(AutofillManagerTest, DisplaySuggestionsWithMatchingTokens) {
+  // Token matching is currently behind a flag.
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      autofill::switches::kEnableSuggestionsWithSubstringMatch);
+
+  // Set up our form data.
+  FormData form;
+  test::CreateTestAddressFormData(&form);
+  std::vector<FormData> forms(1, form);
+  FormsSeen(forms);
+
+  // Simulate displaying suggestions for field contents "gmail", check that
+  // matching ones are displayed.
+  FormFieldData field;
+  test::CreateTestFormField("Email", "email", "gmail", "email", &field);
+  GetAutofillSuggestions(form, field);
+  AutocompleteSuggestionsReturned(std::vector<base::string16>());
+
+  external_delegate_->CheckSuggestions(
+      kDefaultPageID,
+      Suggestion("theking@gmail.com", "Elvis Aaron Presley", "", 1),
+      Suggestion("buddy@gmail.com", "Charles Hardin Holley", "", 2));
+}
+
+// Test that suggestions which do not have a prefix match or prefix-token match
+// with the field contents are not matched.
+TEST_F(AutofillManagerTest, NoSuggestionForNonPrefixTokenMatch) {
+  // Token matching is currently behind a flag.
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      autofill::switches::kEnableSuggestionsWithSubstringMatch);
+
+  // Set up our form data.
+  FormData form;
+  test::CreateTestAddressFormData(&form);
+  std::vector<FormData> forms(1, form);
+  FormsSeen(forms);
+
+  // Simulate displaying suggestions for field contents "mail". Check that none
+  // appear, because none has a token with a prefix "mail".
+  FormFieldData field;
+  test::CreateTestFormField("Email", "email", "mail", "email", &field);
+  GetAutofillSuggestions(form, field);
+  EXPECT_FALSE(external_delegate_->on_suggestions_returned_seen());
+}
+
+// Test matching when field contents contains suggestion token separators.
+TEST_F(AutofillManagerTest, MatchingContentsWithSuggestionTokenSeparator) {
+  // Token matching is currently behind a flag.
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      autofill::switches::kEnableSuggestionsWithSubstringMatch);
+
+  // Set up our form data.
+  FormData form;
+  test::CreateTestAddressFormData(&form);
+  std::vector<FormData> forms(1, form);
+  FormsSeen(forms);
+
+  // Simulate displaying suggestions for field contents "buddy@gma", check that
+  // matching one is displayed. Please also note here that field contents
+  // contains token separators '@', |IsContentsPrefixOfSuggestionToken()| only
+  // picks suggestions that passes 2 constrains; firstly whether field contents
+  // is a substring of suggestions, and secondly whether character right before
+  // suggestions offset is one of the splitting characters. In our test case,
+  // only "buddy@gmail.com" passes both the constrains and apparently we could
+  // see only that in matching suggestion list.
+  FormFieldData field;
+  test::CreateTestFormField("Email", "email", "buddy@gma", "email", &field);
+  GetAutofillSuggestions(form, field);
+  AutocompleteSuggestionsReturned(std::vector<base::string16>());
+
+  external_delegate_->CheckSuggestions(
+      kDefaultPageID,
+      Suggestion("buddy@gmail.com", "Charles Hardin Holley", "", 1));
+}
+
 }  // namespace autofill