[Autofill] Autofill fails to show suggestions for credit card split across fields.

components/autofill/core/browser/autofill_field_unittest.cc

Index: components/autofill/core/browser/autofill_field_unittest.cc
diff --git a/components/autofill/core/browser/autofill_field_unittest.cc b/components/autofill/core/browser/autofill_field_unittest.cc
index fa10822aa1c0210ac82fb724c0bd9faad825953d..d95af5fd67728df4ec7c45e33a05d2a2cf4db6e0 100644
--- a/components/autofill/core/browser/autofill_field_unittest.cc
+++ b/components/autofill/core/browser/autofill_field_unittest.cc
@@ -49,6 +49,32 @@ size_t GetNumberOffset(size_t index, const TestCase& test) {
   return result;
 }
 
+// Helper function to test |GetCreditCardNumberValue()|.
+void TestGetCreditCardNumberValue(const TestCase& test) {
+  size_t offset = 0;
+  for (size_t i = 0; i < test.total_spilts_; ++i) {
+    AutofillField cc_number_part;
+    cc_number_part.set_heuristic_type(CREDIT_CARD_NUMBER);
+    cc_number_part.max_length = test.splits_[i];
+    offset += (i == 0) ? 0 : test.splits_[i - 1];
+    cc_number_part.set_credit_card_number_offset(offset);
+
+    // Retrive the value for |cc_number_part|.
+    base::string16 actual = AutofillField::GetCreditCardNumberValue(
+        cc_number_part, ASCIIToUTF16(test.card_number_));
+
+    // Enforce the field's |max_length| constraint. Please note that, normally
+    // this would be handled on renderer, which is why it needs to be specially
+    // handled in the unit test.
+    actual = (offset < test.card_number_.length())
+                 ? actual.substr(0, test.splits_[i])
+                 : base::string16();
+
+    // Verify for expected results.
+    EXPECT_EQ(ASCIIToUTF16(test.expected_results_[i]), actual);
+  }
+}
+
 TEST(AutofillFieldTest, Type) {
   AutofillField field;
   ASSERT_EQ(NO_SERVER_DATA, field.server_type());
@@ -622,5 +648,59 @@ TEST(AutofillFieldTest, FillCreditCardNumberWithUnequalSizeSplits) {
   EXPECT_EQ(ASCIIToUTF16(test.card_number_), cc_number_full.value);
 }
 
+TEST(AutofillFieldTest, GetCreditCardNumberValue_OffsetsLessThanDigits) {
+  TestCase test;
+  test.card_number_ = "5187654321098765";
+
+  // Offset for all card number input fields are less than the size of digits on
+  // the card.
+  size_t max_lengths[] = {4, 4, 4, 4};
+  std::string expectations[] = {"5187", "6543", "2109", "8765"};
+  test.total_spilts_ = arraysize(max_lengths);
+  test.splits_ =
+      std::vector<int>(max_lengths, max_lengths + arraysize(max_lengths));
+  test.expected_results_ = std::vector<std::string>(
+      expectations, expectations + arraysize(expectations));
+
+  // Verify against the expectations.
+  TestGetCreditCardNumberValue(test);
+}
+
+TEST(AutofillFieldTest, GetCreditCardNumberValue_OffsetsEqualsDigits) {
+  TestCase test;
+  test.card_number_ = "5187654321098765";
+
+  // Offset for second card number input field is equals to the size of digits
+  // on the card.
+  size_t max_lengths[] = {16, 4};
+  std::string expectations[] = {"5187654321098765", std::string()};
+  test.total_spilts_ = arraysize(max_lengths);
+  test.splits_ =
+      std::vector<int>(max_lengths, max_lengths + arraysize(max_lengths));
+  test.expected_results_ = std::vector<std::string>(
+      expectations, expectations + arraysize(expectations));
+
+  // Verify against the expectations.
+  TestGetCreditCardNumberValue(test);
+}
+
+TEST(AutofillFieldTest, GetCreditCardNumberValue_OffsetsGreaterThanDigits) {
+  TestCase test;
+  test.card_number_ = "5187654321098765";
+
+  // Offset for second card number input field is greater than the size of
+  // digits on the card.
+  size_t max_lengths[] = {20, 16};
+  std::string expectations[] = {"5187654321098765", std::string()};
+  test.total_spilts_ = arraysize(max_lengths);
+  test.splits_ =
+      std::vector<int>(max_lengths, max_lengths + arraysize(max_lengths));
+  test.expected_results_ = std::vector<std::string>(
+      expectations, expectations + arraysize(expectations));
+
+  // Verify against the expectations.
+  TestGetCreditCardNumberValue(test);
+}
+
 }  // namespace
 }  // namespace autofill