Some coverage fixes

Author: fjarri

src/hazmat.rs

@@ -52,4 +52,11 @@ mod tests {
         assert!(Primality::Prime != Primality::ProbablyPrime);
         assert_eq!(Primality::Prime.clone(), Primality::Prime);
     }
+
+    #[test]
+    fn primality_to_bool() {
+        assert!(Primality::Prime.is_probably_prime());
+        assert!(Primality::ProbablyPrime.is_probably_prime());
+        assert!(!Primality::Composite.is_probably_prime());
+    }
 }

src/hazmat/miller_rabin.rs

@@ -109,7 +109,7 @@ mod tests {
 
     use crypto_bigint::{Uint, U1024, U128, U1536, U64};
     use rand_chacha::ChaCha8Rng;
-    use rand_core::{CryptoRngCore, SeedableRng};
+    use rand_core::{CryptoRngCore, OsRng, SeedableRng};
 
     #[cfg(feature = "tests-exhaustive")]
     use num_prime::nt_funcs::is_prime64;
@@ -124,6 +124,21 @@ mod tests {
         assert_eq!(mr.clone(), mr);
     }
 
+    #[test]
+    #[should_panic(expected = "`candidate` must be odd.")]
+    fn parity_check() {
+        let _mr = MillerRabin::new(&U64::from(10u32));
+    }
+
+    #[test]
+    #[should_panic(
+        expected = "No suitable random base possible when `candidate == 3`; use the base 2 test."
+    )]
+    fn random_base_range_check() {
+        let mr = MillerRabin::new(&U64::from(3u32));
+        mr.test_random_base(&mut OsRng);
+    }
+
     fn is_spsp(num: u32) -> bool {
         pseudoprimes::STRONG_BASE_2.iter().any(|x| *x == num)
     }

src/presets.rs

@@ -145,10 +145,8 @@ fn _is_prime_with_rng<const L: usize>(rng: &mut impl CryptoRngCore, num: &Uint<L
     debug_assert!(bool::from(num.is_odd()));
     let mr = MillerRabin::new(num);
 
-    match mr.test_base_two() {
-        Primality::Composite => return false,
-        Primality::Prime => return true,
-        _ => {}
+    if !mr.test_base_two().is_probably_prime() {
+        return false;
     }
 
     match lucas_test(num, SelfridgeBase, LucasCheck::Strong) {
@@ -158,12 +156,8 @@ fn _is_prime_with_rng<const L: usize>(rng: &mut impl CryptoRngCore, num: &Uint<L
     }
 
     // The random base test only makes sense when `num > 3`.
-    if num.bits() > 2 {
-        match mr.test_random_base(rng) {
-            Primality::Composite => return false,
-            Primality::Prime => return true,
-            _ => {}
-        }
+    if num.bits() > 2 && !mr.test_random_base(rng).is_probably_prime() {
+        return false;
     }
 
     true