From 9b4c0e9c5a83709a82e11af7930ce7e740d6ae77 Mon Sep 17 00:00:00 2001
From: Callum Fortune <callumfortune03@outlook.com>
Date: Sat, 27 Apr 2024 00:52:09 +0100
Subject: [PATCH] Fix negative number hanging error

---
 src/miller_rabin.rs        |  5 +++++
 tests/miller_rabin_test.rs | 14 ++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/miller_rabin.rs b/src/miller_rabin.rs
index 9d7e534..be33836 100644
--- a/src/miller_rabin.rs
+++ b/src/miller_rabin.rs
@@ -4,6 +4,11 @@ use num_integer::Integer;
 use rand::thread_rng;
 
 pub fn miller_rabin(candidate: &BigInt) -> bool {
+
+    if candidate < &BigInt::from(0) {
+        return false;
+    }
+
     if candidate.is_even() {
         return *candidate == BigInt::from(2); // 2 is prime
     }
diff --git a/tests/miller_rabin_test.rs b/tests/miller_rabin_test.rs
index 0b000e6..3aea250 100644
--- a/tests/miller_rabin_test.rs
+++ b/tests/miller_rabin_test.rs
@@ -5,6 +5,20 @@ mod tests {
     use super::*;
     use num_bigint::BigInt;
 
+    #[test]
+    fn test_negative_numbers() {
+
+        let primes = vec![
+            BigInt::from(-150),
+            BigInt::from(-3),
+            BigInt::from(0),
+            BigInt::from(-1005050)
+        ];
+        for prime in primes {
+            assert_eq!(miller_rabin(&prime), false);
+        }
+    }
+
     #[test]
     fn test_primes() {