Add range insertion for base::flat_tree

base/containers/flat_tree_unittest.cc

Index: base/containers/flat_tree_unittest.cc
diff --git a/base/containers/flat_tree_unittest.cc b/base/containers/flat_tree_unittest.cc
index e3a8f879fcf82de71e6951a91c48c7b223d98b96..669a925021be974a7a72c12136e9f0fcca6a2675 100644
--- a/base/containers/flat_tree_unittest.cc
+++ b/base/containers/flat_tree_unittest.cc
@@ -31,8 +31,6 @@
 //   this.
 // * No tests with min_allocator and no tests counting allocations.
 //   Flat sets currently don't support allocators.
-// * No tests for range insertion. Flat sets currently do not support this
-//   functionality.
 
 #include <string>
 #include <vector>
@@ -738,6 +736,42 @@ TEST(FlatTree, InsertPositionRValue) {
   EXPECT_EQ(3, result->data());
 }
 
+// template <class InputIterator>
+//   void insert(InputIterator first, InputIterator last);
+
+TEST(FlatTree, InsertIterIter) {
+  struct GetKeyFromIntIntPair {
+    int operator()(const std::pair<int, int>& p) const { return p.first; }
+  };
+
+  using IntIntMap =
+      flat_tree<int, IntPair, GetKeyFromIntIntPair, std::less<int>>;
+  IntIntMap cont;
+
+  {
+    IntPair int_pairs[] = {{3, 1}, {1, 1}, {4, 1}, {2, 1}};
+    cont.insert(std::begin(int_pairs), std::end(int_pairs));
+    EXPECT_THAT(cont, ElementsAre(IntPair(1, 1), IntPair(2, 1), IntPair(3, 1),
+                                  IntPair(4, 1)));
+  }
+
+  {
+    IntPair int_pairs[] = {{3, 2}, {1, 2}, {4, 2}, {2, 2}};
+    cont.insert(std::begin(int_pairs), std::end(int_pairs));
+    EXPECT_THAT(cont, ElementsAre(IntPair(1, 1), IntPair(2, 1), IntPair(3, 1),
+                                  IntPair(4, 1)));
+  }
+
+  {
+    IntPair int_pairs[] = {{3, 2}, {1, 2}, {4, 2}, {2, 2}, {7, 2}, {6, 2},
+                           {8, 2}, {5, 2}, {5, 3}, {6, 3}, {7, 3}, {8, 3}};
+    cont.insert(std::begin(int_pairs), std::end(int_pairs));
+    EXPECT_THAT(cont, ElementsAre(IntPair(1, 1), IntPair(2, 1), IntPair(3, 1),
+                                  IntPair(4, 1), IntPair(5, 2), IntPair(6, 2),
+                                  IntPair(7, 2), IntPair(8, 2)));
+  }

[dyaroshev, 2017/05/09 09:32:46]

An empty range check is important.

Maybe we want to generate some inputs and check against those? Doesn't seem that
hard.

[jdoerrie, 2017/05/09 17:03:30]

Done.

+}
+
 // template <class... Args>
 // pair<iterator, bool> emplace(Args&&... args)