Implementing erase/erase_if functions from library fundamentals ts:

base/stl_util_unittest.cc

 // Copyright 2012 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 "base/stl_util.h"
 
+#include <deque>
+#include <forward_list>
+#include <functional>
+#include <iterator>
+#include <list>
+#include <map>
 #include <set>
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
 
+#include "base/containers/flat_set.h"
+#include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 // Used as test case to ensure the various base::STLXxx functions don't require
 // more than operators "<" and "==" on values stored in containers.
 class ComparableValue {
  public:
   explicit ComparableValue(int value) : value_(value) {}
 
   bool operator==(const ComparableValue& rhs) const {
     return value_ == rhs.value_;
   }
 
   bool operator<(const ComparableValue& rhs) const {
     return value_ < rhs.value_;
   }
 
  private:
   int value_;
 };
 
+template <typename Container>
+void RunStlEraseTest() {
+  const std::pair<Container, Container> test_data[] = {
+      {{}, {}}, {{1, 2, 3}, {1, 3}}, {{1, 2, 3, 2}, {1, 3}}};
+
+  for (auto test_case : test_data) {
+    base::STLErase(test_case.first, 2);
+    EXPECT_EQ(test_case.second, test_case.first);
+  }
+}
+
+// This test is written for containers of std::pair<int, int> to support maps.
+template <typename Container>
+void RunStlEraseIfTest() {
+  auto PairFromInt = [](int num) { return std::make_pair(num, num); };
+  struct {
+    Container input;
+    Container erase_even;
+    Container erase_odd;
+  } test_data[] = {
+      {{}, {}, {}},
+      {{PairFromInt(1), PairFromInt(2), PairFromInt(3)},

[Peter Kasting, 2017/03/01 03:20:11]

Nit: This all seems longer than just writing {1, 1}, {2, 2}, {3, 3}.

+       {PairFromInt(1), PairFromInt(3)},
+       {PairFromInt(2)}},
+      {{PairFromInt(1), PairFromInt(2), PairFromInt(3), PairFromInt(4)},
+       {PairFromInt(1), PairFromInt(3)},
+       {PairFromInt(2), PairFromInt(4)}},
+  };
+
+  for (auto test_case : test_data) {
+    base::STLEraseIf(test_case.input, [](const std::pair<int, int>& elem) {
+      return !(elem.first & 1);
+    });
+    EXPECT_EQ(test_case.erase_even, test_case.input);
+  }
+
+  for (auto test_case : test_data) {
+    base::STLEraseIf(test_case.input, [](const std::pair<int, int>& elem) {
+      return elem.first & 1;
+    });
+    EXPECT_EQ(test_case.erase_odd, test_case.input);
+  }
+}
+
+struct HashByFirst {
+  size_t operator()(const std::pair<int, int>& elem) const {
+    return std::hash<int>()(elem.first);
+  }
+};
+
 }  // namespace
 
 namespace base {
 namespace {
 
 TEST(STLUtilTest, STLIsSorted) {
   {
     std::set<int> set;
     set.insert(24);
     set.insert(1);
@@ skipping 215 matching lines @@
   // With a COW implementation, this test will fail if
   // string_as_array(&str) is implemented as
   // const_cast<char*>(str->data()).
   std::string s1("abc");
   const std::string s2(s1);
   string_as_array(&s1)[1] = 'x';
   EXPECT_EQ("axc", s1);
   EXPECT_EQ("abc", s2);
 }
 
+TEST(STLErase, String) {
+  const std::pair<std::string, std::string> test_data[] = {
+      {"", ""}, {"abc", "bc"}, {"abca", "bc"},
+  };
+
+  for (auto test_case : test_data) {
+    STLErase(test_case.first, 'a');
+    EXPECT_EQ(test_case.second, test_case.first);
+  }
+
+  for (auto test_case : test_data) {
+    STLEraseIf(test_case.first, [](char elem) { return elem < 'b'; });
+    EXPECT_EQ(test_case.second, test_case.first);
+  }
+}
+
+TEST(STLErase, String16) {
+  std::pair<base::string16, base::string16> test_data[] = {
+      {base::string16(), base::string16()},
+      {UTF8ToUTF16("abc"), UTF8ToUTF16("bc")},
+      {UTF8ToUTF16("abca"), UTF8ToUTF16("bc")},
+  };
+
+  const base::string16 letters = UTF8ToUTF16("ab");
+  for (auto test_case : test_data) {
+    STLErase(test_case.first, letters[0]);
+    EXPECT_EQ(test_case.second, test_case.first);
+  }
+
+  for (auto test_case : test_data) {
+    STLEraseIf(test_case.first, [&](short elem) { return elem < letters[1]; });
+    EXPECT_EQ(test_case.second, test_case.first);
+  }
+}
+
+TEST(STLErase, Deque) {
+  RunStlEraseTest<std::deque<int>>();
+  RunStlEraseIfTest<std::deque<std::pair<int, int>>>();
+}
+
+TEST(STLErase, Vector) {
+  RunStlEraseTest<std::vector<int>>();
+  RunStlEraseIfTest<std::vector<std::pair<int, int>>>();
+}
+
+TEST(STLErase, ForwardList) {
+  RunStlEraseTest<std::forward_list<int>>();
+  RunStlEraseIfTest<std::forward_list<std::pair<int, int>>>();
+}
+
+TEST(STLErase, List) {
+  RunStlEraseTest<std::list<int>>();
+  RunStlEraseIfTest<std::list<std::pair<int, int>>>();
+}
+
+TEST(STLErase, Map) {
+  RunStlEraseIfTest<std::map<int, int>>();
+}
+
+TEST(STLErase, Multimap) {
+  RunStlEraseIfTest<std::multimap<int, int>>();
+}
+
+TEST(STLErase, Set) {
+  RunStlEraseIfTest<std::set<std::pair<int, int>>>();
+}
+
+TEST(STLErase, Multiset) {
+  RunStlEraseIfTest<std::multiset<std::pair<int, int>>>();
+}
+
+TEST(STLErase, UnorderedMap) {
+  RunStlEraseIfTest<std::unordered_map<int, int>>();
+}
+
+TEST(STLErase, UnorderedMultimap) {
+  RunStlEraseIfTest<std::unordered_multimap<int, int>>();
+}
+
+TEST(STLErase, UnorderedSet) {
+  RunStlEraseIfTest<std::unordered_set<std::pair<int, int>, HashByFirst>>();
+}
+
+TEST(STLErase, UnorderedMultiset) {
+  RunStlEraseIfTest<
+      std::unordered_multiset<std::pair<int, int>, HashByFirst>>();
+}
+
+TEST(STLErase, FlatSet) {
+  RunStlEraseIfTest<base::flat_set<std::pair<int, int>>>();
+}
+
 }  // namespace
 }  // namespace base