diff --git a/cmake/sdksCommon.cmake b/cmake/sdksCommon.cmake
index 6206d961af3..4cc041d3ccf 100644
--- a/cmake/sdksCommon.cmake
+++ b/cmake/sdksCommon.cmake
@@ -167,6 +167,7 @@ list(APPEND SDK_TEST_PROJECT_LIST "monitoring:tests/aws-cpp-sdk-monitoring-integ
 list(APPEND SDK_TEST_PROJECT_LIST "rds:tests/aws-cpp-sdk-rds-integration-tests")
 list(APPEND SDK_TEST_PROJECT_LIST "redshift:tests/aws-cpp-sdk-redshift-integration-tests")
 list(APPEND SDK_TEST_PROJECT_LIST "s3:tests/aws-cpp-sdk-s3-integration-tests")
+list(APPEND SDK_TEST_PROJECT_LIST "s3:tests/aws-cpp-sdk-s3-unit-tests")
 list(APPEND SDK_TEST_PROJECT_LIST "s3-crt:tests/aws-cpp-sdk-s3-crt-integration-tests")
 list(APPEND SDK_TEST_PROJECT_LIST "s3-encryption:tests/aws-cpp-sdk-s3-encryption-tests,tests/aws-cpp-sdk-s3-encryption-integration-tests")
 list(APPEND SDK_TEST_PROJECT_LIST "s3control:tests/aws-cpp-sdk-s3control-integration-tests")
diff --git a/tests/aws-cpp-sdk-s3-unit-tests/CMakeLists.txt b/tests/aws-cpp-sdk-s3-unit-tests/CMakeLists.txt
new file mode 100644
index 00000000000..a2b351012d9
--- /dev/null
+++ b/tests/aws-cpp-sdk-s3-unit-tests/CMakeLists.txt
@@ -0,0 +1,32 @@
+add_project(aws-cpp-sdk-s3-unit-tests
+        "Unit Tests for the S3 SDK Client"
+        aws-cpp-sdk-s3
+        testing-resources
+        aws_test_main
+        aws-cpp-sdk-core)
+
+add_definitions(-DRESOURCES_DIR="${CMAKE_CURRENT_SOURCE_DIR}/resources")
+
+if(MSVC AND BUILD_SHARED_LIBS)
+    add_definitions(-DGTEST_LINKED_AS_SHARED_LIBRARY=1)
+endif()
+
+enable_testing()
+
+if(PLATFORM_ANDROID AND BUILD_SHARED_LIBS)
+    add_library(${PROJECT_NAME} ${CMAKE_CURRENT_SOURCE_DIR}/S3UnitTests.cpp)
+else()
+    add_executable(${PROJECT_NAME} ${CMAKE_CURRENT_SOURCE_DIR}/S3UnitTests.cpp)
+endif()
+
+set_compiler_flags(${PROJECT_NAME})
+set_compiler_warnings(${PROJECT_NAME})
+
+target_link_libraries(${PROJECT_NAME} ${PROJECT_LIBS})
+
+if(MSVC AND BUILD_SHARED_LIBS)
+    set_target_properties(${PROJECT_NAME} PROPERTIES LINK_FLAGS "/DELAYLOAD:aws-cpp-sdk-s3.dll /DELAYLOAD:aws-cpp-sdk-core.dll")
+endif()
+
+include(GoogleTest)
+gtest_discover_tests(${PROJECT_NAME})
diff --git a/tests/aws-cpp-sdk-s3-unit-tests/S3UnitTests.cpp b/tests/aws-cpp-sdk-s3-unit-tests/S3UnitTests.cpp
new file mode 100644
index 00000000000..664e7780c27
--- /dev/null
+++ b/tests/aws-cpp-sdk-s3-unit-tests/S3UnitTests.cpp
@@ -0,0 +1,93 @@
+#include <gtest/gtest.h>
+#include <aws/core/Aws.h>
+#include <aws/core/auth/AWSCredentials.h>
+#include <aws/s3/S3Client.h>
+#include <aws/s3/model/PutObjectRequest.h>
+#include <aws/testing/mocks/http/MockHttpClient.h>
+#include <aws/testing/AwsTestHelpers.h>
+
+using namespace Aws;
+using namespace Aws::Auth;
+using namespace Aws::Http;
+using namespace Aws::S3;
+using namespace Aws::S3::Model;
+
+const char* ALLOCATION_TAG = "S3UnitTest";
+
+class S3UnitTest : public testing::Test {
+protected:
+  void SetUp() override {
+    _mockClientFactory = Aws::MakeShared<MockHttpClientFactory>(ALLOCATION_TAG);
+    _mockHttpClient = Aws::MakeShared<MockHttpClient>(ALLOCATION_TAG);
+    _mockClientFactory->SetClient(_mockHttpClient);
+    HttpOptions httpOptions;
+    httpOptions.httpClientFactory_create_fn = [this]() -> std::shared_ptr<HttpClientFactory> {
+      return _mockClientFactory;
+    };
+    _options.httpOptions = httpOptions;
+    InitAPI(_options);
+    AWSCredentials credentials{"mock", "credentials"};
+    _s3Client = Aws::MakeUnique<S3Client>("ALLOCATION_TAG", credentials);
+  }
+
+  void TearDown() override {
+    ShutdownAPI(_options);
+  }
+
+  SDKOptions _options;
+  std::shared_ptr<MockHttpClient> _mockHttpClient;
+  std::shared_ptr<MockHttpClientFactory> _mockClientFactory;
+  UniquePtr<S3Client> _s3Client;
+};
+
+
+TEST_F(S3UnitTest, S3UriLeadingDots) {
+  auto putObjectRequest = PutObjectRequest()
+      .WithBucket("bluerev")
+      .WithKey("../BoredInBristol");
+
+  std::shared_ptr<IOStream> body = Aws::MakeShared<StringStream>(ALLOCATION_TAG,
+    "Bored in Bristol, always waiting",
+    std::ios_base::in | std::ios_base::binary);
+
+  putObjectRequest.SetBody(body);
+
+  //We have to mock requset because it is used to create the return body, it actually isnt used.
+  auto mockRequest = Aws::MakeShared<Standard::StandardHttpRequest>(ALLOCATION_TAG, "mockuri", HttpMethod::HTTP_GET);
+  mockRequest->SetResponseStreamFactory([]() -> IOStream* {
+    IOStream* stream = Aws::New<StringStream>(ALLOCATION_TAG, "response-string", std::ios_base::in | std::ios_base::binary);
+    return stream;
+  });
+  auto mockResponse = Aws::MakeShared<Standard::StandardHttpResponse>(ALLOCATION_TAG, mockRequest);
+  mockResponse->SetResponseCode(HttpResponseCode::OK);
+  _mockHttpClient->AddResponseToReturn(mockResponse);
+  const auto response = _s3Client->PutObject(putObjectRequest);
+  AWS_EXPECT_SUCCESS(response);
+  const auto seenRequest = _mockHttpClient->GetMostRecentHttpRequest();
+  EXPECT_EQ("https://bluerev.s3.us-east-1.amazonaws.com/../BoredInBristol", seenRequest.GetUri().GetURIString());
+}
+
+TEST_F(S3UnitTest, S3UriMiddleDots) {
+  auto putObjectRequest = PutObjectRequest()
+      .WithBucket("bluerev")
+      .WithKey("belinda/../says");
+
+  std::shared_ptr<IOStream> body = Aws::MakeShared<StringStream>(ALLOCATION_TAG,
+    "Blue Rev behind the rink I didn't really need it",
+    std::ios_base::in | std::ios_base::binary);
+
+  putObjectRequest.SetBody(body);
+
+  //We have to mock requset because it is used to create the return body, it actually isnt used.
+  auto mockRequest = Aws::MakeShared<Standard::StandardHttpRequest>(ALLOCATION_TAG, "mockuri", HttpMethod::HTTP_GET);
+  mockRequest->SetResponseStreamFactory([]() -> IOStream* {
+    return Aws::New<StringStream>(ALLOCATION_TAG, "response-string", std::ios_base::in | std::ios_base::binary);
+  });
+  auto mockResponse = Aws::MakeShared<Standard::StandardHttpResponse>(ALLOCATION_TAG, mockRequest);
+  mockResponse->SetResponseCode(HttpResponseCode::OK);
+  _mockHttpClient->AddResponseToReturn(mockResponse);
+  const auto response = _s3Client->PutObject(putObjectRequest);
+  AWS_EXPECT_SUCCESS(response);
+  const auto seenRequest = _mockHttpClient->GetMostRecentHttpRequest();
+  EXPECT_EQ("https://bluerev.s3.us-east-1.amazonaws.com/belinda/../says", seenRequest.GetUri().GetURIString());
+}
diff --git a/tests/testing-resources/CMakeLists.txt b/tests/testing-resources/CMakeLists.txt
index 179a65fbc72..0711dd14a8d 100644
--- a/tests/testing-resources/CMakeLists.txt
+++ b/tests/testing-resources/CMakeLists.txt
@@ -109,9 +109,12 @@ endif()
 
 add_library(${PROJECT_NAME} ${TestingResources_SRC})
 add_library(AWS::${PROJECT_NAME} ALIAS ${PROJECT_NAME})
+add_library(aws_test_main source/external/gtest/src/gtest_main.cc)
 
 set_compiler_flags(${PROJECT_NAME})
 set_compiler_warnings(${PROJECT_NAME})
+set_compiler_flags(aws_test_main)
+set_compiler_warnings(aws_test_main)
 
 if(PLATFORM_CUSTOM)
   add_custom_testing_target_compile_definitions()
@@ -123,6 +126,12 @@ target_include_directories(${PROJECT_NAME} PUBLIC
         $<INSTALL_INTERFACE:include>)
 target_link_libraries(${PROJECT_NAME} ${PLATFORM_DEP_LIBS} ${PROJECT_LIBS})
 
+target_include_directories(aws_test_main PUBLIC
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include/aws/external>
+        $<INSTALL_INTERFACE:include>)
+
+target_link_libraries(aws_test_main ${PROJECT_NAME})
+
 if(COMMAND add_custom_testing_link_libraries)
     add_custom_testing_link_libraries()
 endif()
diff --git a/tools/scripts/run_integration_tests.py b/tools/scripts/run_integration_tests.py
index dd964eb8a28..cd7dbed9fda 100644
--- a/tools/scripts/run_integration_tests.py
+++ b/tools/scripts/run_integration_tests.py
@@ -40,6 +40,7 @@ def main():
         "aws-cpp-sdk-dynamodb-integration-tests",
         "aws-cpp-sdk-sqs-integration-tests",
         "aws-cpp-sdk-s3-integration-tests",
+        "aws-cpp-sdk-s3-unit-tests",
         #"aws-cpp-sdk-s3-crt-integration-tests",
         #"aws-cpp-sdk-s3control-integration-tests",
         # "aws-cpp-sdk-lambda-integration-tests",