[Translate] Add unit tests for TranslateManager

We will be looking at changing the target language algorithm. As a
preparation for that, adding unit tests to establish a baseline.

BUG=569219
R=hajimehoshi@chromium.org

Review URL: https://codereview.chromium.org/1523113002

Cr-Commit-Position: refs/heads/master@{#365419}

3 files changed, 65 insertions, 1 deletions

diff --git a/components/translate/core/browser/translate_download_manager.cc b/components/translate/core/browser/translate_download_manager.cc
index fd5ad58..75a9ee65 100644
--- a/components/translate/core/browser/translate_download_manager.cc
+++ b/components/translate/core/browser/translate_download_manager.cc
@@ -97,7 +97,6 @@ bool TranslateDownloadManager::IsSupportedLanguage(
     NOTREACHED();
     return false;
   }
-
   return language_list->IsSupportedLanguage(language);
 }
 
diff --git a/components/translate/core/browser/translate_language_list_unittest.cc b/components/translate/core/browser/translate_language_list_unittest.cc
index fac731e..539deec 100644
--- a/components/translate/core/browser/translate_language_list_unittest.cc
+++ b/components/translate/core/browser/translate_language_list_unittest.cc
@@ -24,6 +24,7 @@ TEST(TranslateLanguageListTest, SetSupportedLanguages) {
   ASSERT_EQ(2u, results.size());
   EXPECT_EQ("en", results[0]);
   EXPECT_EQ("ja", results[1]);
+  manager->ResetForTesting();
 }
 
 TEST(TranslateLanguageListTest, SetSupportedLanguagesWithAlphaKey) {
@@ -42,6 +43,7 @@ TEST(TranslateLanguageListTest, SetSupportedLanguagesWithAlphaKey) {
   ASSERT_EQ(2u, results.size());
   EXPECT_EQ("en", results[0]);
   EXPECT_EQ("ja", results[1]);
+  manager->ResetForTesting();
 }
 
 }  // namespace translate
diff --git a/components/translate/core/browser/translate_manager_unittest.cc b/components/translate/core/browser/translate_manager_unittest.cc
new file mode 100644
index 0000000..0bd0dbe
--- /dev/null
+++ b/components/translate/core/browser/translate_manager_unittest.cc
@@ -0,0 +1,63 @@
+// Copyright 2015 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 "components/translate/core/browser/translate_manager.h"
+
+#include "components/translate/core/browser/translate_download_manager.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace translate {
+
+// Target language comes from application locale if the locale's language
+// is supported.
+TEST(TranslateManagerTest, GetTargetLanguageDefaultsToAppLocale) {
+  std::vector<std::string> accept_language_list;
+
+  // Ensure we're not requesting a server-side translate language list.
+  TranslateLanguageList::DisableUpdate();
+
+  // Ensure the locale is set to a supported language.
+  ASSERT_TRUE(TranslateDownloadManager::IsSupportedLanguage("en"));
+  TranslateDownloadManager* manager = TranslateDownloadManager::GetInstance();
+  manager->ResetForTesting();
+  manager->set_application_locale("en");
+  EXPECT_EQ("en", TranslateManager::GetTargetLanguage(accept_language_list));
+
+  // Try a second supported language.
+  ASSERT_TRUE(TranslateDownloadManager::IsSupportedLanguage("de"));
+  manager->set_application_locale("de");
+  EXPECT_EQ("de", TranslateManager::GetTargetLanguage(accept_language_list));
+}
+
+// If the application locale's language is not supported, the target language
+// falls back to the first supported language in |accept_languages_list|. If
+// none of the languages in |accept_language_list| is supported, the target
+// language is empty.
+TEST(TranslateManagerTest, GetTargetLanguageAcceptLangFallback) {
+  std::vector<std::string> accept_language_list;
+
+  // Ensure we're not requesting a server-side translate language list.
+  TranslateLanguageList::DisableUpdate();
+
+  // Ensure locale is set to a not-supported language.
+  ASSERT_FALSE(TranslateDownloadManager::IsSupportedLanguage("xy"));
+  TranslateDownloadManager* manager = TranslateDownloadManager::GetInstance();
+  manager->ResetForTesting();
+  manager->set_application_locale("xy");
+
+  // Default return is empty string.
+  EXPECT_EQ("", TranslateManager::GetTargetLanguage(accept_language_list));
+
+  // Unsupported languages still result in the empty string.
+  ASSERT_FALSE(TranslateDownloadManager::IsSupportedLanguage("xy"));
+  accept_language_list.push_back("xy");
+  EXPECT_EQ("", TranslateManager::GetTargetLanguage(accept_language_list));
+
+  // First supported language is the fallback language.
+  ASSERT_TRUE(TranslateDownloadManager::IsSupportedLanguage("en"));
+  accept_language_list.push_back("en");
+  EXPECT_EQ("en", TranslateManager::GetTargetLanguage(accept_language_list));
+}
+
+}  // namespace translate