Add a IoTester class

tests/io_tester.cpp

@@ -0,0 +1,30 @@
+#include "io_tester.hpp"
+#include "catch.hpp"
+#include <iostream>
+
+/**
+ * Directly test this class here
+ */
+TEST_CASE()
+{
+  {
+    IoTester<std::ostream> out(std::cout);
+    std::cout << "test";
+    CHECK(out.str() == "test");
+  }
+  {
+    IoTester<std::ostream> out(std::cout);
+    CHECK(out.str().empty());
+  }
+}
+
+TEST_CASE()
+{
+  {
+    IoTester<std::istream> is(std::cin);
+    is.set_string("coucou");
+    std::string res;
+    std::cin >> res;
+    CHECK(res == "coucou");
+  }
+}

tests/io_tester.hpp

@@ -0,0 +1,47 @@
+#ifndef BIBOUMI_IO_TESTER_HPP
+#define BIBOUMI_IO_TESTER_HPP
+
+#include <ostream>
+#include <sstream>
+
+/**
+ * Redirects a stream into a streambuf until the object is destroyed.
+ */
+template <typename StreamType>
+class IoTester
+{
+public:
+  IoTester(StreamType& ios):
+    stream{},
+    ios(ios),
+    old_buf(ios.rdbuf())
+  {
+    // Redirect the given os into our stringstream’s buf
+    this->ios.rdbuf(this->stream.rdbuf());
+  }
+  ~IoTester()
+  {
+    this->ios.rdbuf(this->old_buf);
+  }
+  IoTester& operator=(const IoTester&) = delete;
+  IoTester& operator=(IoTester&&) = delete;
+  IoTester(const IoTester&) = delete;
+  IoTester(IoTester&&) = delete;
+
+  std::string str() const
+  {
+    return this->stream.str();
+  }
+
+  void set_string(const std::string& s)
+  {
+    this->stream.str(s);
+  }
+
+private:
+  std::stringstream stream;
+  StreamType& ios;
+  std::streambuf* const old_buf;
+};
+
+#endif //BIBOUMI_IO_TESTER_HPP