diff --git a/Cargo.toml b/Cargo.toml
index 9c8887431..bcf9a7615 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -329,6 +329,7 @@ pin_same-file = { version="1.0.4, < 1.0.6", package="same-file" } ## same-file v
 pin_winapi-util = { version="0.1.2, < 0.1.3", package="winapi-util" } ## winapi-util v0.1.3 has compiler errors for MinRustV v1.32.0, expects 1.34
 
 [dev-dependencies]
+conv = "0.3"
 filetime = "0.2"
 libc = "0.2"
 rand = "0.7"
diff --git a/tests/by-util/test_factor.rs b/tests/by-util/test_factor.rs
index 33c184ba0..5bde17cdb 100644
--- a/tests/by-util/test_factor.rs
+++ b/tests/by-util/test_factor.rs
@@ -10,15 +10,15 @@ use std::time::SystemTime;
 
 #[path = "../../src/uu/factor/sieve.rs"]
 mod sieve;
-use self::sieve::Sieve;
 
+extern crate conv;
 extern crate rand;
+
 use self::rand::distributions::{Distribution, Uniform};
 use self::rand::{rngs::SmallRng, Rng, SeedableRng};
+use self::sieve::Sieve;
 
 const NUM_PRIMES: usize = 10000;
-const LOG_PRIMES: f64 = 14.0; // ceil(log2(NUM_PRIMES))
-
 const NUM_TESTS: usize = 100;
 
 #[test]
@@ -44,6 +44,9 @@ fn test_first_100000_integers() {
 
 #[test]
 fn test_random() {
+    use conv::prelude::*;
+
+    let log_num_primes = f64::value_from(NUM_PRIMES).unwrap().log2().ceil();
     let primes = Sieve::primes().take(NUM_PRIMES).collect::<Vec<u64>>();
 
     let rng_seed = SystemTime::now()
@@ -51,16 +54,16 @@ fn test_random() {
         .unwrap()
         .as_secs();
     println!("rng_seed={:?}", rng_seed);
-
     let mut rng = SmallRng::seed_from_u64(rng_seed);
+
     let mut rand_gt = move |min: u64| {
-        let mut product = 1u64;
+        let mut product = 1_u64;
         let mut factors = Vec::new();
         while product < min {
             // log distribution---higher probability for lower numbers
             let factor;
             loop {
-                let next = rng.gen_range(0f64, LOG_PRIMES).exp2().floor() as usize;
+                let next = rng.gen_range(0_f64, log_num_primes).exp2().floor() as usize;
                 if next < NUM_PRIMES {
                     factor = primes[next];
                     break;
@@ -106,7 +109,8 @@ fn test_random_big() {
         .as_secs();
     println!("rng_seed={:?}", rng_seed);
     let mut rng = SmallRng::seed_from_u64(rng_seed);
-    let bitrange_1 = Uniform::new(14usize, 51);
+
+    let bitrange_1 = Uniform::new(14_usize, 51);
     let mut rand_64 = move || {
         // first, choose a random number of bits for the first factor
         let f_bit_1 = bitrange_1.sample(&mut rng);
@@ -116,11 +120,11 @@ fn test_random_big() {
         // we will have a number of additional factors equal to nfacts + 1
         // where nfacts is in [0, floor(rem/14) )  NOTE half-open interval
         // Each prime factor is at least 14 bits, hence floor(rem/14)
-        let nfacts = Uniform::new(0usize, rem / 14).sample(&mut rng);
+        let nfacts = Uniform::new(0_usize, rem / 14).sample(&mut rng);
         // we have to distribute extrabits among the (nfacts + 1) values
         let extrabits = rem - (nfacts + 1) * 14;
         // (remember, a Range is a half-open interval)
-        let extrarange = Uniform::new(0usize, extrabits + 1);
+        let extrarange = Uniform::new(0_usize, extrabits + 1);
 
         // to generate an even split of this range, generate n-1 random elements
         // in the range, add the desired total value to the end, sort this list,
@@ -147,7 +151,7 @@ fn test_random_big() {
         let f_bits = f_bits;
 
         let mut nbits = 0;
-        let mut product = 1u64;
+        let mut product = 1_u64;
         let mut factors = Vec::new();
         for bit in f_bits {
             assert!(bit < 37);