Adding utility for getting symbols out of the symbol table

Author: thk123

unit/testing-utils/require_symbol.cpp

@@ -0,0 +1,24 @@
+/*******************************************************************\
+
+ Module: Unit test utilities
+
+ Author: DiffBlue Limited. All rights reserved.
+
+\*******************************************************************/
+
+
+#include "require_symbol.h"
+#include "catch.hpp"
+
+/// Verify whether a given identifier is found in the symbol table and return it
+/// \param symbol_table: The symbol table to look in
+/// \param symbol_identifier: The name of the symbol
+const symbolt &require_symbol::require_symbol_exists(
+  const symbol_tablet &symbol_table,
+  const irep_idt &symbol_identifier)
+{
+  const symbolt *found_symbol=symbol_table.lookup(symbol_identifier);
+  INFO("Looking for symbol: " + id2string(symbol_identifier));
+  REQUIRE(found_symbol != nullptr);
+  return *found_symbol;
+}

unit/testing-utils/require_symbol.h

@@ -0,0 +1,26 @@
+/*******************************************************************\
+
+ Module: Unit test utilities
+
+ Author: DiffBlue Limited. All rights reserved.
+
+\*******************************************************************/
+
+#ifndef CPROVER_TESTING_UTILS_REQUIRE_SYMBOL_H
+#define CPROVER_TESTING_UTILS_REQUIRE_SYMBOL_H
+
+#include <util/symbol.h>
+#include <util/symbol_table.h>
+
+/// \file
+/// Helper functions for getting symbols from the symbol table during unit tests
+
+// NOLINTNEXTLINE(readability/namespace)
+namespace require_symbol
+{
+const symbolt &require_symbol_exists(
+  const symbol_tablet &symbol_table,
+  const irep_idt &symbol_identifier);
+}
+
+#endif //CPROVER_TESTING_UTILS_REQUIRE_SYMBOL_H