add simple test for timing checks

phf_generator/Cargo.toml

@@ -10,3 +10,9 @@ edition = "2018"
 [dependencies]
 rand = { version = "0.7", features = ["small_rng"] }
 phf_shared = { version = "0.7.24", path = "../phf_shared" }
+# for stable black_box()
+criterion = { version = "0.2", optional = true }
+
+[[bin]]
+name = "gen_hash_test"
+required-features = ["criterion"]

phf_generator/src/bin/gen_hash_test.rs

@@ -0,0 +1,18 @@
+use criterion::*;
+
+use rand::distributions::Alphanumeric;
+use rand::rngs::SmallRng;
+use rand::{Rng, SeedableRng};
+
+use phf_generator::generate_hash;
+
+fn gen_vec(len: usize) -> Vec<String> {
+    let mut rng = SmallRng::seed_from_u64(0xAAAAAAAAAAAAAAAA).sample_iter(Alphanumeric);
+
+    (0 .. len).map(move |_| rng.by_ref().take(64).collect::<String>()).collect()
+}
+
+fn main() {
+    let data = black_box(gen_vec(1_000_000));
+    black_box(generate_hash(&data));
+}