Combine all tests in a single executable to speed up the build

tests/libtransmission/subprocess-test-program.cc

@@ -0,0 +1,71 @@
+/*
+ * This file Copyright (C) 2017 Mnemosyne LLC
+ *
+ * It may be used under the GNU GPL versions 2 or 3
+ * or any future license endorsed by Mnemosyne LLC.
+ *
+ */
+
+#include "transmission.h"
+#include "file.h"
+#include "subprocess.h"
+#include "utils.h"
+
+#include <memory>
+#include <string>
+
+int main(int argc, char** argv)
+{
+    if (argc < 3)
+    {
+        return 1;
+    }
+
+    auto const result_path = std::string{ argv[1] };
+    auto const test_action = std::string{ argv[2] };
+    auto const tmp_result_path = result_path + ".tmp";
+
+    auto fd = tr_sys_file_open(
+        tmp_result_path.data(), // NOLINT
+        TR_SYS_FILE_WRITE | TR_SYS_FILE_CREATE | TR_SYS_FILE_TRUNCATE,
+        0644,
+        nullptr);
+
+    if (fd == TR_BAD_SYS_FILE)
+    {
+        return 1;
+    }
+
+    if (test_action == "--dump-args")
+    {
+        for (size_t i = 3; i < argc; ++i)
+        {
+            tr_sys_file_write_line(fd, argv[i], nullptr);
+        }
+    }
+    else if (test_action == "--dump-env")
+    {
+        for (size_t i = 3; i < argc; ++i)
+        {
+            char* const value = tr_env_get_string(argv[i], "<null>");
+            tr_sys_file_write_line(fd, value, nullptr);
+            tr_free(value);
+        }
+    }
+    else if (test_action == "--dump-cwd")
+    {
+        char* const value = tr_sys_dir_get_current(nullptr);
+        tr_sys_file_write_line(fd, value != nullptr ? value : "<null>", nullptr);
+        tr_free(value);
+    }
+    else
+    {
+        tr_sys_file_close(fd, nullptr);
+        tr_sys_path_remove(tmp_result_path.data(), nullptr);
+        return 1;
+    }
+
+    tr_sys_file_close(fd, nullptr);
+    tr_sys_path_rename(tmp_result_path.data(), result_path.data(), nullptr);
+    return 0;
+}