Merge pull request #1589 (from nbraud:factor/gcd/test_divisor)

src/uu/factor/src/numeric/gcd.rs

@@ -72,11 +72,14 @@ mod tests {
             gcd(1, a) == 1
         }
 
+        fn zero(a: u64) -> bool {
+            gcd(0, a) == a
+        }
+
         fn divisor(a: u64, b: u64) -> bool {
             // Test that gcd(a, b) divides a and b
             let g = gcd(a, b);
-            if g == 0 { return a == 0 && b == 0; }
-            a % g == 0 && b % g == 0
+            (g != 0 && a % g == 0 && b % g == 0) || (g == 0 && a == 0 && b == 0)
         }
 
         fn commutative(a: u64, b: u64) -> bool {