stderr capture in tests

Author: Vardan2009

tests/runner.cpp

@@ -10,9 +10,9 @@
 
 std::string runInterpreter(const std::string& file) {
 #if defined(_WIN32)
-    std::string command = "eigerc -s \"" + file + "\"";
+    std::string command = "eigerc -s \"" + file + "\" 2>&1";
 #else
-    std::string command = "./eigerc -s \"" + file + "\"";
+    std::string command = "./eigerc -s \"" + file + "\" 2>&1";
 #endif
 
     FILE* pipe = popen(command.c_str(), "r");

tests/variables.eig.out

@@ -4,4 +4,4 @@
 10
 100
 20
-RUNTIME_ERROR: Variable y is not defined at line 21
+RUNTIME_ERROR: Symbol y is unbound at line 21