test: adding new test for fibonacci subject to check for recursivity …

…and usage of loops

tests/fibonacci_test/main.go

@@ -1,14 +1,85 @@
 package main
 
 import (
-	student "student"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"log"
+	"reflect"
+	"runtime"
 
+	student "student"
 	"github.com/01-edu/go-tests/lib/challenge"
 	"github.com/01-edu/go-tests/lib/random"
 	"github.com/01-edu/go-tests/solutions"
 )
 
+// CheckFunctionStructure analyzes if the provided function is recursive and ensures it contains no loops.
+func CheckFunctionStructure(f interface{}) error {
+	// Get the file path of the loaded function using reflection
+	funcPtr := reflect.ValueOf(f).Pointer()
+	funcDetails := runtime.FuncForPC(funcPtr)
+	funcFile, _ := funcDetails.FileLine(funcPtr)
+	funcName := funcDetails.Name() // Retrieve the function name
+
+
+	fset := token.NewFileSet()
+
+	// Parse the source file to create an AST
+	node, err := parser.ParseFile(fset, funcFile, nil, parser.AllErrors)
+	if err != nil {
+		return fmt.Errorf("failed to parse file: %v", err)
+	}
+
+	// Variables to track recursion and loop usage
+	var isRecursive, hasLoop bool
+
+	// Traverse the AST to locate the function and check for recursion and loops
+	ast.Inspect(node, func(n ast.Node) bool {
+		// Locate the function declaration by matching the function name
+		if fn, ok := n.(*ast.FuncDecl); ok && fn.Name.Name == "Fibonacci" {
+
+			// Traverse the function body to check for recursive calls and loops
+			ast.Inspect(fn.Body, func(n ast.Node) bool {
+				switch stmt := n.(type) {
+				case *ast.CallExpr:
+					// Check if the function calls itself (recursion)
+					if ident, ok := stmt.Fun.(*ast.Ident); ok && ident.Name == fn.Name.Name {
+						isRecursive = true // Recursive call detected
+					}
+				case *ast.ForStmt:
+					// Detect any "for" loop
+					hasLoop = true
+				case *ast.RangeStmt:
+					// Detect any "range" loop
+					hasLoop = true
+				}
+				return true
+			})
+			return false // Stop further inspection after analyzing the function
+		}
+		return true
+	})
+
+	// Check results and return appropriate errors
+	if hasLoop {
+		return fmt.Errorf("the function %s contains a loop, which is not allowed", funcName)
+	}
+	if !isRecursive {
+		return fmt.Errorf("the function %s is not recursive", funcName)
+	}
+	return nil
+}
+
 func main() {
+	// Check the structure of the student's Fibonacci implementation
+	err := CheckFunctionStructure(student.Fibonacci)
+	if err != nil {
+		log.Fatalf("Error: %v\n", err)
+	}
+
+	// Generate test cases for the function
 	args := append(random.IntSliceBetween(0, 25),
 		4,
 		5,