add invalid test case

llama/extraction/extract_test.go

@@ -56,6 +56,7 @@ var testCases = []struct {
 	{"Go Extraction 4 - If Else", "```go\nif x > 10 {\nfmt.Println('Greater than 10')\n} else {\nfmt.Println('Less than or equal to 10')\n}\n```", "\nif x > 10 {\nfmt.Println('Greater than 10')\n} else {\nfmt.Println('Less than or equal to 10')\n}\n"},
 	{"Go Extraction 5 - Function with Parameters", "```go\nfunc add(a int, b int) int {\nreturn a + b\n}\n```", "\nfunc add(a int, b int) int {\nreturn a + b\n}\n"},
 	{"Go Extraction 6 - Nested Loops", "```go\nfor i := 0; i < 3; i++ {\nfor j := 0; j < 3; j++ {\nfmt.Printf('(%d, %d)', i, j)\n}\n}\n```", "\nfor i := 0; i < 3; i++ {\nfor j := 0; j < 3; j++ {\nfmt.Printf('(%d, %d)', i, j)\n}\n}\n"},
+	{"Go Extraction 7 - Invalid", "```go```", ""},
 
 	// Rust Test Cases
 	{"Rust Extraction 1 - Main", "```rust\nfn main() {}\n```", "\nfn main() {}\n"},