Add separate allocators test

test/unittest/CMakeLists.txt

 set(UNITTEST_SOURCES
+	allocatorstest.cpp
     bigintegertest.cpp
     documenttest.cpp
     encodedstreamtest.cpp

test/unittest/allocatorstest.cpp

+// Copyright (C) 2011 Milo Yip
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "unittest.h"
+
+#include "rapidjson/allocators.h"
+
+using namespace rapidjson;
+
+template <typename Allocator>
+void TestAllocator(Allocator& a) {
+    uint8_t* p = (uint8_t*)a.Malloc(100);
+    EXPECT_TRUE(p != 0);
+    for (size_t i = 0; i < 100; i++)
+        p[i] = (uint8_t)i;
+
+    // Expand
+    uint8_t* q = (uint8_t*)a.Realloc(p, 100, 200);
+    EXPECT_TRUE(q != 0);
+    for (size_t i = 0; i < 100; i++)
+        EXPECT_EQ(i, q[i]);
+    for (size_t i = 100; i < 200; i++)
+        q[i] = (uint8_t)i;
+
+    // Shrink
+    uint8_t *r = (uint8_t*)a.Realloc(q, 200, 150);
+    EXPECT_TRUE(r != 0);
+    for (size_t i = 0; i < 150; i++)
+        EXPECT_EQ(i, r[i]);
+
+    Allocator::Free(r);
+}
+
+TEST(Allocator, CrtAllocator) {
+    CrtAllocator a;
+    TestAllocator(a);
+}
+
+TEST(Allocator, MemoryPoolAllocator) {
+    MemoryPoolAllocator<> a;
+    TestAllocator(a);
+
+    for (int i = 0; i < 1000; i++) {
+        EXPECT_TRUE(a.Malloc(i) != 0);
+        EXPECT_LE(a.Size(), a.Capacity());
+    }
+}