chore: add abstraction for opening output files to be able to mock it

test/ObjCommonTestUtils/SearchPath/MockOutputPath.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "SearchPath/IOutputPath.h"
+
+#include <sstream>
+#include <string>
+#include <vector>
+
+class MockOutputFile
+{
+public:
+    std::string m_name;
+    std::string m_data;
+
+    MockOutputFile();
+    MockOutputFile(std::string name, std::string data);
+};
+
+class MockOutputPath final : public IOutputPath
+{
+public:
+    std::unique_ptr<std::ostream> Open(const std::string& fileName) override;
+
+    [[nodiscard]] const MockOutputFile* GetMockedFile(const std::string& name) const;
+
+private:
+    std::vector<MockOutputFile> m_files;
+};