Add rtc::Optional equality/unequality comparisions with object

webrtc/base/optional_unittest.cc

 /*
  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 638 matching lines @@
       V("0:17. explicit constructor", "1:42. explicit constructor",
         "2:17. copy constructor (from 0:17)",
         "3:17. copy constructor (from 0:17)",
         "4:42. copy constructor (from 1:42)", "---", "operator== 2:17, 2:17",
         "operator== 2:17, 3:17", "operator!= 2:17, 4:42", "---",
         "4:42. destructor", "3:17. destructor", "2:17. destructor",
         "1:42. destructor", "0:17. destructor"),
       *log);
 }
 
+TEST(OptionalTest, TestEqualityWithObject) {
+  auto log = Logger::Setup();
+  {
+    Logger a(17), b(42);
+    Optional<Logger> ma(a), me;
+    // Using operator== and operator!= explicetly instead of EXPECT_EQ/EXPECT_NE
+    // macros because those operators are under test.
+    log->push_back("---");
+
+    EXPECT_TRUE(ma == a);
+    EXPECT_TRUE(a == ma);
+    EXPECT_FALSE(ma == b);
+    EXPECT_FALSE(b == ma);
+    EXPECT_FALSE(me == a);
+    EXPECT_FALSE(a == me);
+
+    EXPECT_FALSE(ma != a);
+    EXPECT_FALSE(a != ma);
+    EXPECT_TRUE(ma != b);
+    EXPECT_TRUE(b != ma);
+    EXPECT_TRUE(me != a);
+    EXPECT_TRUE(a != me);
+
+    log->push_back("---");
+  }
+  // clang-format off
+  EXPECT_EQ(V("0:17. explicit constructor",
+              "1:42. explicit constructor",
+              "2:17. copy constructor (from 0:17)",
+              "---",
+              "operator== 2:17, 0:17",
+              "operator== 0:17, 2:17",
+              "operator== 2:17, 1:42",
+              "operator== 1:42, 2:17",
+              // No operator should be called when comparing to empty.
+              "operator!= 2:17, 0:17",
+              "operator!= 0:17, 2:17",
+              "operator!= 2:17, 1:42",
+              "operator!= 1:42, 2:17",
+              // No operator should be called when comparing to empty.
+              "---",
+              "2:17. destructor",
+              "1:42. destructor",
+              "0:17. destructor"),
+            *log);
+  // clang-format on
+}
+
 TEST(OptionalTest, TestSwap) {
   auto log = Logger::Setup();
   {
     Logger a(17), b(42);
     Optional<Logger> x1(a), x2(b), y1(a), y2, z1, z2;
     log->push_back("---");
     swap(x1, x2);  // Swap full <-> full.
     swap(y1, y2);  // Swap full <-> empty.
     swap(z1, z2);  // Swap empty <-> empty.
     log->push_back("---");
   }
   EXPECT_EQ(V("0:17. explicit constructor", "1:42. explicit constructor",
               "2:17. copy constructor (from 0:17)",
               "3:42. copy constructor (from 1:42)",
               "4:17. copy constructor (from 0:17)", "---", "swap 2:42, 3:17",
               "5:17. move constructor (from 4:17)", "4:17. destructor", "---",
               "5:17. destructor", "3:17. destructor", "2:42. destructor",
               "1:42. destructor", "0:17. destructor"),
             *log);
 }
 
 }  // namespace rtc