feat: add dependency

javascript-engine/external/getrandom/tests/common/mod.rs

@@ -0,0 +1,100 @@
+use super::getrandom_impl;
+
+#[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+use wasm_bindgen_test::wasm_bindgen_test as test;
+
+#[cfg(feature = "test-in-browser")]
+wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);
+
+#[test]
+fn test_zero() {
+    // Test that APIs are happy with zero-length requests
+    getrandom_impl(&mut [0u8; 0]).unwrap();
+}
+
+// Return the number of bits in which s1 and s2 differ
+#[cfg(not(feature = "custom"))]
+fn num_diff_bits(s1: &[u8], s2: &[u8]) -> usize {
+    assert_eq!(s1.len(), s2.len());
+    s1.iter()
+        .zip(s2.iter())
+        .map(|(a, b)| (a ^ b).count_ones() as usize)
+        .sum()
+}
+
+// Tests the quality of calling getrandom on two large buffers
+#[test]
+#[cfg(not(feature = "custom"))]
+fn test_diff() {
+    let mut v1 = [0u8; 1000];
+    getrandom_impl(&mut v1).unwrap();
+
+    let mut v2 = [0u8; 1000];
+    getrandom_impl(&mut v2).unwrap();
+
+    // Between 3.5 and 4.5 bits per byte should differ. Probability of failure:
+    // ~ 2^(-94) = 2 * CDF[BinomialDistribution[8000, 0.5], 3500]
+    let d = num_diff_bits(&v1, &v2);
+    assert!(d > 3500);
+    assert!(d < 4500);
+}
+
+// Tests the quality of calling getrandom repeatedly on small buffers
+#[test]
+#[cfg(not(feature = "custom"))]
+fn test_small() {
+    // For each buffer size, get at least 256 bytes and check that between
+    // 3 and 5 bits per byte differ. Probability of failure:
+    // ~ 2^(-91) = 64 * 2 * CDF[BinomialDistribution[8*256, 0.5], 3*256]
+    for size in 1..=64 {
+        let mut num_bytes = 0;
+        let mut diff_bits = 0;
+        while num_bytes < 256 {
+            let mut s1 = vec![0u8; size];
+            getrandom_impl(&mut s1).unwrap();
+            let mut s2 = vec![0u8; size];
+            getrandom_impl(&mut s2).unwrap();
+
+            num_bytes += size;
+            diff_bits += num_diff_bits(&s1, &s2);
+        }
+        assert!(diff_bits > 3 * num_bytes);
+        assert!(diff_bits < 5 * num_bytes);
+    }
+}
+
+#[test]
+fn test_huge() {
+    let mut huge = [0u8; 100_000];
+    getrandom_impl(&mut huge).unwrap();
+}
+
+// On WASM, the thread API always fails/panics
+#[cfg(not(target_arch = "wasm32"))]
+#[test]
+fn test_multithreading() {
+    extern crate std;
+    use std::{sync::mpsc::channel, thread, vec};
+
+    let mut txs = vec![];
+    for _ in 0..20 {
+        let (tx, rx) = channel();
+        txs.push(tx);
+
+        thread::spawn(move || {
+            // wait until all the tasks are ready to go.
+            rx.recv().unwrap();
+            let mut v = [0u8; 1000];
+
+            for _ in 0..100 {
+                getrandom_impl(&mut v).unwrap();
+                thread::yield_now();
+            }
+        });
+    }
+
+    // start all the tasks
+    for tx in txs.iter() {
+        tx.send(()).unwrap();
+    }
+}