[Payments] Basic validation in the credit card editor.

chrome/browser/ui/views/payments/validating_textfield_unittest.cc

+// Copyright 2017 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 "chrome/browser/ui/views/payments/validating_textfield.h"
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace payments {
+
+class ValidatingTextfieldTest : public testing::Test,
+                                public ValidatingTextfield::Delegate {
+ public:
+  ValidatingTextfieldTest() {}
+  ~ValidatingTextfieldTest() override {}
+
+  // ValidatingTextfield::Delegate
+  bool ValidateTextfield(ValidatingTextfield* textfield) override {
+    // We really don't like textfields with more than 5 characters in them.
+    return textfield->text().size() <= 5u;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ValidatingTextfieldTest);
+};
+
+TEST_F(ValidatingTextfieldTest, Validation) {
+  std::unique_ptr<ValidatingTextfield> textfield(new ValidatingTextfield(this));
+
+  // Set an invalid string (>5 characters).
+  textfield->SetText(base::ASCIIToUTF16("evilstring"));
+  // This should be called on new contents by the textfield controller.
+  textfield->OnContentsChanged();
+
+  // Not marked as invalid.
+  EXPECT_FALSE(textfield->invalid());
+
+  // On blur though, there is a first validation.
+  textfield->OnBlur();
+  EXPECT_TRUE(textfield->invalid());
+
+  // On further text adjustements, the validation runs now. Set a valid string
+  // (<=5 characters).
+  textfield->SetText(base::ASCIIToUTF16("good"));
+  textfield->OnContentsChanged();
+
+  // No longer invalid.
+  EXPECT_FALSE(textfield->invalid());
+}
+
+}  // namespace payments