factor: Move benchmarks out-of-crate

Cargo.toml

@@ -324,6 +324,9 @@ wc       = { optional=true, version="0.0.6", package="uu_wc", path="src/uu/wc" }
 who      = { optional=true, version="0.0.6", package="uu_who", path="src/uu/who" }
 whoami   = { optional=true, version="0.0.6", package="uu_whoami", path="src/uu/whoami" }
 yes      = { optional=true, version="0.0.6", package="uu_yes", path="src/uu/yes" }
+
+factor_benches = { optional = true, version = "0.0.0", package = "uu_factor_benches", path = "tests/benches/factor" }
+
 #
 # * pinned transitive dependencies
 # Not needed for now. Keep as examples:

src/uu/factor/BENCHMARKING.md

@@ -1,15 +1,18 @@
 # Benchmarking `factor`
 
+The benchmarks for `factor` are located under `tests/benches/factor`
+and can be invoked with `cargo bench` in that directory.
+
+They are located outside the `uu_factor` crate, as they do not comply
+with the project's minimum supported Rust version, *i.e.* may require
+a newer version of `rustc`.
+
+
 ## Microbenchmarking deterministic functions
 
 We currently use [`criterion`] to benchmark deterministic functions,
 such as `gcd` and `table::factor`.
 
-Those benchmarks can be simply executed with `cargo bench` as usual,
-but may require a recent version of Rust, *i.e.* the project's minimum
-supported version of Rust does not apply to the benchmarks.
-
-
 However, µbenchmarks are by nature unstable: not only are they specific to
 the hardware, operating system version, etc., but they are noisy and affected
 by other tasks on the system (browser, compile jobs, etc.), which can cause

src/uu/factor/Cargo.toml

@@ -23,19 +23,9 @@ uucore = { version=">=0.0.8", package="uucore", path="../../uucore" }
 uucore_procs = { version = ">=0.0.5", package = "uucore_procs", path = "../../uucore_procs" }
 
 [dev-dependencies]
-array-init = "2.0.0"
-criterion = "0.3"
 paste = "0.1.18"
 quickcheck = "0.9.2"
-rand_chacha = "0.2.2"
 
-[[bench]]
-name = "gcd"
-harness = false
-
-[[bench]]
-name = "table"
-harness = false
 
 [[bin]]
 name = "factor"

tests/benches/factor/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "uu_factor_benches"
+version = "0.0.0"
+authors = ["nicoo <nicoo@debian.org>"]
+license = "MIT"
+description = "Benchmarks for the uu_factor integer factorization tool"
+homepage = "https://github.com/uutils/coreutils"
+edition = "2018"
+
+[dependencies]
+uu_factor = { path = "../../../src/uu/factor" }
+
+[dev-dependencies]
+array-init = "2.0.0"
+criterion = "0.3"
+rand = "0.7"
+rand_chacha = "0.2.2"
+
+
+[[bench]]
+name = "gcd"
+harness = false
+
+[[bench]]
+name = "table"
+harness = false