diff --git a/quic/platform/api/quic_str_cat_test.cc b/quic/platform/api/quic_str_cat_test.cc
new file mode 100644
index 0000000..c8f1724
--- /dev/null
+++ b/quic/platform/api/quic_str_cat_test.cc
@@ -0,0 +1,167 @@
+// Copyright (c) 2016 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 "net/third_party/quiche/src/quic/platform/api/quic_str_cat.h"
+
+#include "net/third_party/quiche/src/quic/platform/api/quic_string.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_string_piece.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_test.h"
+
+namespace quic {
+namespace test {
+namespace {
+
+class QuicStrCatTest : public QuicTest {};
+
+TEST_F(QuicStrCatTest, Ints) {
+  const int16_t s = -1;
+  const uint16_t us = 2;
+  const int i = -3;
+  const uint32_t ui = 4;
+  const int64_t l = -5;
+  const uint64_t ul = 6;
+  const ptrdiff_t ptrdiff = -7;
+  const size_t size = 8;
+  const intptr_t intptr = -9;
+  const uintptr_t uintptr = 10;
+  QuicString answer;
+  answer = QuicStrCat(s, us);
+  EXPECT_EQ(answer, "-12");
+  answer = QuicStrCat(i, ui);
+  EXPECT_EQ(answer, "-34");
+  answer = QuicStrCat(l, ul);
+  EXPECT_EQ(answer, "-56");
+  answer = QuicStrCat(ptrdiff, size);
+  EXPECT_EQ(answer, "-78");
+  answer = QuicStrCat(size, intptr);
+  EXPECT_EQ(answer, "8-9");
+  answer = QuicStrCat(uintptr, 0);
+  EXPECT_EQ(answer, "100");
+}
+
+TEST_F(QuicStrCatTest, Basics) {
+  QuicString result;
+
+  QuicString strs[] = {"Hello", "Cruel", "World"};
+
+  QuicStringPiece pieces[] = {"Hello", "Cruel", "World"};
+
+  const char* c_strs[] = {"Hello", "Cruel", "World"};
+
+  int32_t i32s[] = {'H', 'C', 'W'};
+  uint64_t ui64s[] = {12345678910LL, 10987654321LL};
+
+  result = QuicStrCat(false, true, 2, 3);
+  EXPECT_EQ(result, "0123");
+
+  result = QuicStrCat(-1);
+  EXPECT_EQ(result, "-1");
+
+  result = QuicStrCat(0.5);
+  EXPECT_EQ(result, "0.5");
+
+  result = QuicStrCat(strs[1], pieces[2]);
+  EXPECT_EQ(result, "CruelWorld");
+
+  result = QuicStrCat(strs[0], ", ", pieces[2]);
+  EXPECT_EQ(result, "Hello, World");
+
+  result = QuicStrCat(strs[0], ", ", strs[1], " ", strs[2], "!");
+  EXPECT_EQ(result, "Hello, Cruel World!");
+
+  result = QuicStrCat(pieces[0], ", ", pieces[1], " ", pieces[2]);
+  EXPECT_EQ(result, "Hello, Cruel World");
+
+  result = QuicStrCat(c_strs[0], ", ", c_strs[1], " ", c_strs[2]);
+  EXPECT_EQ(result, "Hello, Cruel World");
+
+  result = QuicStrCat("ASCII ", i32s[0], ", ", i32s[1], " ", i32s[2], "!");
+  EXPECT_EQ(result, "ASCII 72, 67 87!");
+
+  result = QuicStrCat(ui64s[0], ", ", ui64s[1], "!");
+  EXPECT_EQ(result, "12345678910, 10987654321!");
+
+  QuicString one = "1";
+  result = QuicStrCat("And a ", one.size(), " and a ", &result[2] - &result[0],
+                      " and a ", one, " 2 3 4", "!");
+  EXPECT_EQ(result, "And a 1 and a 2 and a 1 2 3 4!");
+
+  result =
+      QuicStrCat("To output a char by ASCII/numeric value, use +: ", '!' + 0);
+  EXPECT_EQ(result, "To output a char by ASCII/numeric value, use +: 33");
+
+  float f = 10000.5;
+  result = QuicStrCat("Ten K and a half is ", f);
+  EXPECT_EQ(result, "Ten K and a half is 10000.5");
+
+  double d = 99999.9;
+  result = QuicStrCat("This double number is ", d);
+  EXPECT_EQ(result, "This double number is 99999.9");
+
+  result =
+      QuicStrCat(1, 22, 333, 4444, 55555, 666666, 7777777, 88888888, 999999999);
+  EXPECT_EQ(result, "122333444455555666666777777788888888999999999");
+}
+
+TEST_F(QuicStrCatTest, MaxArgs) {
+  QuicString result;
+  // Test 10 up to 26 arguments, the current maximum
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a");
+  EXPECT_EQ(result, "123456789a");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b");
+  EXPECT_EQ(result, "123456789ab");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c");
+  EXPECT_EQ(result, "123456789abc");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d");
+  EXPECT_EQ(result, "123456789abcd");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e");
+  EXPECT_EQ(result, "123456789abcde");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f");
+  EXPECT_EQ(result, "123456789abcdef");
+  result =
+      QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f", "g");
+  EXPECT_EQ(result, "123456789abcdefg");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h");
+  EXPECT_EQ(result, "123456789abcdefgh");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i");
+  EXPECT_EQ(result, "123456789abcdefghi");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j");
+  EXPECT_EQ(result, "123456789abcdefghij");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k");
+  EXPECT_EQ(result, "123456789abcdefghijk");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k", "l");
+  EXPECT_EQ(result, "123456789abcdefghijkl");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k", "l", "m");
+  EXPECT_EQ(result, "123456789abcdefghijklm");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k", "l", "m", "n");
+  EXPECT_EQ(result, "123456789abcdefghijklmn");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k", "l", "m", "n", "o");
+  EXPECT_EQ(result, "123456789abcdefghijklmno");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k", "l", "m", "n", "o", "p");
+  EXPECT_EQ(result, "123456789abcdefghijklmnop");
+  result = QuicStrCat(1, 2, 3, 4, 5, 6, 7, 8, 9, "a", "b", "c", "d", "e", "f",
+                      "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q");
+  EXPECT_EQ(result, "123456789abcdefghijklmnopq");
+  // No limit thanks to C++11's variadic templates
+  result = QuicStrCat(
+      1, 2, 3, 4, 5, 6, 7, 8, 9, 10, "a", "b", "c", "d", "e", "f", "g", "h",
+      "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w",
+      "x", "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L",
+      "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z");
+  EXPECT_EQ(result,
+            "12345678910abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace quic