factor: Add a first property-based test

Cargo.lock

@@ -1,3 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
 [[package]]
 name = "advapi32-sys"
 version = "0.2.0"
@@ -367,6 +369,15 @@ name = "either"
 version = "1.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "env_logger"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "failure"
 version = "0.1.1"
@@ -670,6 +681,17 @@ name = "quick-error"
 version = "1.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "quickcheck"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "quote"
 version = "0.3.15"
@@ -1313,6 +1335,7 @@ dependencies = [
 name = "uu_factor"
 version = "0.0.1"
 dependencies = [
+ "quickcheck 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "uucore 0.0.4 (git+https://github.com/uutils/uucore.git?branch=canary)",
  "uucore_procs 0.0.4 (git+https://github.com/uutils/uucore.git?branch=canary)",
@@ -2193,6 +2216,7 @@ dependencies = [
 "checksum digest 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e5b29bf156f3f4b3c4f610a25ff69370616ae6e0657d416de22645483e72af0a"
 "checksum dunce 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b2641c4a7c0c4101df53ea572bffdc561c146f6c2eb09e4df02bc4811e3feeb4"
 "checksum either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
+"checksum env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
 "checksum failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "934799b6c1de475a012a02dab0ace1ace43789ee4b99bcfbf1a2e3e8ced5de82"
 "checksum failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cdda555bb90c9bb67a3b670a0f42de8e73f5981524123ad8578aafec8ddb8b"
 "checksum fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
@@ -2234,6 +2258,7 @@ dependencies = [
 "checksum ppv-lite86 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "237a5ed80e274dbc66f86bd59c1e25edc039660be53194b5fe0a482e0f2612ea"
 "checksum proc-macro2 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)" = "beae6331a816b1f65d04c45b078fd8e6c93e8071771f41b8163255bbd8d7c8fa"
 "checksum quick-error 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+"checksum quickcheck 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a44883e74aa97ad63db83c4bf8ca490f02b2fc02f92575e720c8551e843c945f"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
 "checksum rand 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c618c47cd3ebd209790115ab837de41425723956ad3ce2e6a7f09890947cacb9"

src/uu/factor/Cargo.toml

@@ -16,6 +16,9 @@ rand = "0.5"
 uucore = { version="0.0.4", package="uucore", git="https://github.com/uutils/uucore.git", branch="canary" }
 uucore_procs = { version="0.0.4", package="uucore_procs", git="https://github.com/uutils/uucore.git", branch="canary" }
 
+[dev-dependencies]
+quickcheck = "0.9.2"
+
 [[bin]]
 name = "factor"
 path = "src/main.rs"

src/uu/factor/src/factor.rs

@@ -108,6 +108,7 @@ pub fn factor(mut n: u64) -> Factors {
 #[cfg(test)]
 mod tests {
     use super::factor;
+    use quickcheck::quickcheck;
 
     #[test]
     fn factor_recombines_small() {
@@ -135,4 +136,10 @@ mod tests {
             assert!(factor(pseudoprime).product() == pseudoprime);
         }
     }
+
+    quickcheck! {
+        fn factor_recombines(i: u64) -> bool {
+            i == 0 || factor(i).product() == i
+        }
+    }
 }