unittests/ADT/MappedIteratorTest.cpp

   1 //===------ MappedIteratorTest.cpp - Unit tests for mapped_iterator -------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/ADT/STLExtras.h"
  10 #include "gtest/gtest.h"
  11
  12 using namespace llvm;
  13
  14 namespace {
  15
  16 TEST(MappedIteratorTest, ApplyFunctionOnDereference) {
  17   std::vector<int> V({0});
  18
  19   auto I = map_iterator(V.begin(), [](int X) { return X + 1; });
  20
  21   EXPECT_EQ(*I, 1) << "should have applied function in dereference";
  22 }
  23
  24 TEST(MappedIteratorTest, ApplyFunctionOnArrow) {
  25   struct S {
  26     int Z = 0;
  27   };
  28
  29   std::vector<int> V({0});
  30   S Y;
  31   S* P = &Y;
  32
  33   auto I = map_iterator(V.begin(), [&](int X) -> S& { return *(P + X); });
  34
  35   I->Z = 42;
  36
  37   EXPECT_EQ(Y.Z, 42) << "should have applied function during arrow";
  38 }
  39
  40 TEST(MappedIteratorTest, FunctionPreservesReferences) {
  41   std::vector<int> V({1});
  42   std::map<int, int> M({ {1, 1} });
  43
  44   auto I = map_iterator(V.begin(), [&](int X) -> int& { return M[X]; });
  45   *I = 42;
  46
  47   EXPECT_EQ(M[1], 42) << "assignment should have modified M";
  48 }
  49
  50 } // anonymous namespace