Introduce ModSecurityTestContext to encapsulate setup of objects required to execute transactions

- Simplifies memory management on error conditions
- Context will be used in unit tests too, in order to provide
  Transaction related instances.

test/common/modsecurity_test_context.h

@@ -0,0 +1,42 @@
+#ifndef TEST_COMMON_MODSECURITY_TEST_CONTEXT_H_
+#define TEST_COMMON_MODSECURITY_TEST_CONTEXT_H_
+
+#include "modsecurity/modsecurity.h"
+#include "modsecurity/rules_set.h"
+#include "modsecurity/transaction.h"
+#include "custom_debug_log.h"
+
+#include <sstream>
+
+namespace modsecurity_test {
+
+    class ModSecurityTestContext {
+    public:
+        explicit ModSecurityTestContext(const std::string &connector)
+            : m_modsec_rules(new CustomDebugLog) {
+            m_modsec.setConnectorInformation(connector);
+            m_modsec.setServerLogCb(logCb);
+        }
+        ~ModSecurityTestContext() = default;
+
+        modsecurity::Transaction create_transaction() {
+            return modsecurity::Transaction(&m_modsec,
+                                            &m_modsec_rules,
+                                            &m_server_log);
+        }
+
+        modsecurity::ModSecurity m_modsec;
+        modsecurity::RulesSet m_modsec_rules;
+        std::stringstream m_server_log;
+
+    private:
+        static void logCb(void *data, const void *msgv) {
+            const char *msg = reinterpret_cast<const char *>(msgv);
+            std::stringstream *ss = (std::stringstream *)data;
+            *ss << msg << std::endl;
+        }
+    };
+
+} // namespace modsecurity_test
+
+#endif // TEST_COMMON_MODSECURITY_TEST_H_