[TTS] Gather surrounding text on Tap before any UX.

chrome/browser/android/contextualsearch/search_action_unittest.cc

+// Copyright 2016 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/android/contextualsearch/search_action.h"
+
+#include "base/gtest_prod_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using base::string16;
+using base::UTF8ToUTF16;
+using std::pair;
+
+// Tests parts of the SearchAction class.
+class SearchActionTest : public testing::Test {
+ public:
+  SearchActionTest() {}
+  ~SearchActionTest() override {}
+};
+
+TEST_F(SearchActionTest, IsValidCharacterTest) {
+  EXPECT_TRUE(SearchAction::IsValidCharacter('a'));
+  EXPECT_TRUE(SearchAction::IsValidCharacter('A'));
+  EXPECT_TRUE(SearchAction::IsValidCharacter('0'));
+
+  EXPECT_FALSE(SearchAction::IsValidCharacter(','));
+  EXPECT_FALSE(SearchAction::IsValidCharacter(' '));
+  EXPECT_FALSE(SearchAction::IsValidCharacter('-'));
+}
+
+TEST_F(SearchActionTest, FindFocusedWordTest) {
+  // Test finding "word" within this sample string.
+  string16 sample = UTF8ToUTF16("Sample word, text");
+  // Expected range when "word" is found.
+  pair<int, int> expected_word(7, 11);
+  // Expected range for an insertion right after "word".
+  pair<int, int> expected_insertion_after_word(11, 11);
+
+  // Any range inside the word but before the end should return the word.
+  EXPECT_EQ(expected_word, SearchAction::FindFocusedWord(sample, 7, 7));
+  EXPECT_EQ(expected_word, SearchAction::FindFocusedWord(sample, 10, 10));
+  EXPECT_EQ(expected_word, SearchAction::FindFocusedWord(sample, 7, 11));
+
+  // A range just past the word returns an insertion after it.
+  EXPECT_EQ(expected_insertion_after_word,
+            SearchAction::FindFocusedWord(sample, 11, 11));
+}
+
+TEST_F(SearchActionTest, SampleSurroundingsTest) {
+  const int FOCUS_LENGTH = 5;  // length of "focus"
+  int f_s;                      // focus start
+  int f_e;                      // focus end
+  string16 sample;
+  pair<string16, int> expected;
+
+  // Sample big enough to include both ends.
+  sample = UTF8ToUTF16("987654321focus123456789");
+  f_s = 9;
+  f_e = f_s + FOCUS_LENGTH;
+  expected = pair<string16, int>(sample, 0);
+  EXPECT_EQ(expected, SearchAction::SampleSurroundings(sample, f_s, f_e, 100));
+
+  // Sample must trim both ends, trimming 6 off each end.
+  expected = pair<string16, int>(UTF8ToUTF16("321focus123"), 6);
+  EXPECT_EQ(expected, SearchAction::SampleSurroundings(sample, f_s, f_e, 12));
+
+  // With focus near the beginning, extra is shifted to the end.
+  sample = UTF8ToUTF16("321focus123456789");
+  f_s = 3;
+  f_e = f_s + FOCUS_LENGTH;
+  expected = pair<string16, int>(UTF8ToUTF16("321focus12345"), 0);
+  EXPECT_EQ(expected, SearchAction::SampleSurroundings(sample, f_s, f_e, 13));
+
+  // With focus near the end, extra is shifted to the beginning.
+  sample = UTF8ToUTF16("987654321focus123");
+  f_s = 9;
+  f_e = f_s + FOCUS_LENGTH;
+  expected = pair<string16, int>(UTF8ToUTF16("54321focus123"), 4);
+  EXPECT_EQ(expected, SearchAction::SampleSurroundings(sample, f_s, f_e, 13));
+}