C++ HTTP mock server

Library for easier HTTP clients testing using simply defined HTTP mock server.

Dependencies

• libmicrohttpd (package libmicrohttpd-dev on debian based systems).
• cpr (tests only, downloaded as git submodules by default).
• gtest (tests only, downloaded as git submodules by default).
• CMake build system.
• C++11 compiler (G++ 4.9 tested).

CMake options

CPR and GTest libraries are by default downloaded as git submodules, but it can be used with system-wide libraries when following cmake options are used:

• -DUSE_SYSTEM_CPR=ON - Use libcpr from system, do not build it from submodule. Default OFF.
  • -DUSE_SYSTEM_CURL=ON - Use libcurl for libcpr from system, do not build it on its own. Default OFF.
• -DUSE_SYSTEM_GTEST=ON - Use Google Test from system, do not build it from submodule. Default OFF.
• -DUSE_ALL_SYSTEM_LIBS=ON - Use both libcpr and GTest libraries from system paths. Default OFF.

Build

If you are not using CPR and GTest from system, it is necessary to initialize git submodules:

git submodule update --init --recursive

Run following commands to build the library:

mkdir build && cd build
cmake ..
make

Custom installation directory can be specified using cmake -DCMAKE_INSTALL_PREFIX:PATH=some/path option. By default the /usr/local/ will be used on most systems. Installation of the library and headers into defined prefix path is possible with make install command.

How to use it

Here is the quick sample how to use mock server in GTests:

#include <gtest/gtest.h>
#include <string>
#include <httpmockserver/mock_server.h>
#include <httpmockserver/test_environment.h>


class HTTPMock: public httpmock::MockServer {
  public:
    /// Create HTTP server on port 9200
    explicit HTTPMock(int port = 9200): MockServer(port) {}
  private:

    /// Handler called by MockServer on HTTP request.
    Response responseHandler(
            const std::string &url,
            const std::string &method,
            const std::string &data,
            const std::vector<UrlArg> &urlArguments,
            const std::vector<Header> &headers)
    {
        if (method == "POST" && matchesPrefix(url, "/example")) {
            // Do something and return response
            return Response(500, "Fake HTTP response");
        }
        // Return "URI not found" for the undefined methods
        return Response(404, "Not Found");
    }

    /// Return true if \p url starts with \p str.
    bool matchesPrefix(const std::string &url, const std::string &str) const {
        return url.substr(0, str.size()) == str;
    }
};


TEST(MyTest, dummyTest) {
    // Here should be implementation of test case using HTTP server.
    // HTTP requests are processed by HTTPMock::responseHandler(...)
    // I. e.: when HTTP POST request is sent on localhost:9200/example, then
    // response with status code 500 and body "Fake HTTP response" is returned.
}


int main(int argc, char *argv[]) {
    ::testing::InitGoogleTest(&argc, argv);
    ::testing::AddGlobalTestEnvironment(new httpmock::TestEnvironment<HTTPMock>());
    return RUN_ALL_TESTS();
}

If you do not want to rely on hardcoded port number, you can use port searching class. Searching for unused port is done in 1000 iterations by default.

// ... class HTTPMock is same as above

/// Server started in the main().
static httpmock::TestEnvironment<httpmock::MockServerHolder>* mock_server_env = nullptr;

TEST(MyTest, dummyTest) {
    assert(nullptr != mock_server_env);
    const int port = mock_server_env->getMock()->getPort();
    // Here should be implementation of test case using HTTP server.
    // HTTP requests are processed by HTTPMock::responseHandler(...)
    // I. e.: when HTTP POST request is sent on localhost:$port/example, then
    // response with status code 500 and body "Fake HTTP response" is returned.
}

int main(int argc, char *argv[]) {
    ::testing::InitGoogleTest(&argc, argv);
    // startup the server for the tests
    ::testing::Environment * const env = ::testing::AddGlobalTestEnvironment(
            httpmock::createMockServerEnvironment<HTTPMock>(9200));
    // set global env pointer
    mock_server_env
        = dynamic_cast<httpmock::TestEnvironment<httpmock::MockServerHolder> *>(env);
    return RUN_ALL_TESTS();
}

License

Library is licensed under the MIT License.