Add unit tests

test/Common.h

@@ -0,0 +1,99 @@
+/********************************************************************************
+ * Copyright (C) 2014-2020 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH  *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+#ifndef FAIR_LOGGER_TEST_COMMON_H
+#define FAIR_LOGGER_TEST_COMMON_H
+
+#include <fstream>
+#include <functional>
+#include <iostream>
+#include <regex>
+#include <stdexcept>
+#include <sstream>
+#include <string>
+
+#include <stdio.h> // fflush
+#include <unistd.h> // dup, dup2, close
+
+namespace fair
+{
+namespace logger
+{
+namespace test
+{
+
+template<typename ... T>
+auto ToStr(T&&... t) -> std::string
+{
+    std::stringstream ss;
+    (void)std::initializer_list<int>{(ss << t, 0)...};
+    return ss.str();
+}
+
+template<int S>
+class StreamCapturer
+{
+  public:
+    explicit StreamCapturer()
+        : mFd(S)
+        , mOriginalFd(dup(S)) // create a copy of the given file descriptor
+    {
+        char name[] = "/tmp/fairlogger_test_capture.XXXXXX";
+
+        const int capturedFd = mkstemp(name); // create a unique temporary file
+        if (capturedFd == -1) {
+            std::cout << "Could not create tmp file " << name << " for test; does the test have access to the /tmp directory?" << std::endl;
+            throw std::runtime_error("Could not create tmp file for test; does the test have access to the /tmp directory?");
+        }
+        mTmpFile = name;
+
+        fflush(nullptr); // flushes all open output streams
+        dup2(capturedFd, mFd);
+        close(capturedFd);
+    }
+
+    std::string GetCapture()
+    {
+        fflush(nullptr); // flushes all open output streams
+        std::ifstream t(mTmpFile);
+        std::stringstream buffer;
+        buffer << t.rdbuf();
+        return buffer.str();
+    }
+
+    ~StreamCapturer()
+    {
+        dup2(mOriginalFd, mFd);
+        close(mOriginalFd);
+        remove(mTmpFile.c_str());
+    }
+
+  private:
+    const int mFd;
+    int mOriginalFd;
+    std::string mTmpFile;
+};
+
+void CheckOutput(std::string const& expected, std::function<void()> f)
+{
+    std::string output;
+    {
+        StreamCapturer<1> c;
+        f();
+        output = c.GetCapture();
+    }
+    const std::regex e(expected);
+    if (!std::regex_match(output, e)) {
+        throw std::runtime_error(std::string("MISMATCH:\n##### expected (regex):\n" + expected + "\n##### found:\n" + output));
+    }
+}
+
+} // namespace test
+} // namespace logger
+} // namespace fair
+
+#endif // FAIR_LOGGER_TEST_COMMON_H