test_fuzz_xof

src/test.rs

@@ -519,6 +519,42 @@ fn test_fuzz_hasher() {
     }
 }
 
+#[test]
+fn test_fuzz_xof() {
+    let mut input_buf = [0u8; 3 * BLOCK_LEN];
+    paint_test_input(&mut input_buf);
+
+    // Don't do too many iterations in debug mode, to keep the tests under a
+    // second or so. CI should run tests in release mode also. Provide an
+    // environment variable for specifying a larger number of fuzz iterations.
+    let num_tests = if cfg!(debug_assertions) { 100 } else { 2500 };
+
+    // Use a fixed RNG seed for reproducibility.
+    let mut rng = rand_chacha::ChaCha8Rng::from_seed([1; 32]);
+    for _num_test in 0..num_tests {
+        #[cfg(feature = "std")]
+        dbg!(_num_test);
+        // 31 (16 + 8 + 4 + 2 + 1) outputs
+        let mut output_buf = [0; 31 * CHUNK_LEN];
+        let input_len = rng.gen_range(0..input_buf.len());
+        let mut xof = crate::Hasher::new()
+            .update(&input_buf[..input_len])
+            .finalize_xof();
+        let partial_start = rng.gen_range(0..output_buf.len());
+        let partial_end = rng.gen_range(partial_start..output_buf.len());
+        xof.fill(&mut output_buf[..partial_start]);
+        xof.fill(&mut output_buf[partial_start..partial_end]);
+        xof.fill(&mut output_buf[partial_end..]);
+
+        let mut reference_buf = [0; 31 * CHUNK_LEN];
+        let mut reference_hasher = reference_impl::Hasher::new();
+        reference_hasher.update(&input_buf[..input_len]);
+        reference_hasher.finalize(&mut reference_buf);
+
+        assert_eq!(reference_buf, output_buf);
+    }
+}
+
 #[test]
 fn test_xof_seek() {
     let mut out = [0; 533];