also test getrandom directly

test-cargo-miri/Cargo.lock

@@ -1,5 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "byteorder"
 version = "1.3.4"
@@ -12,6 +14,7 @@ version = "0.1.0"
 dependencies = [
  "byteorder",
  "cdylib",
+ "getrandom 0.2.2",
  "issue_1567",
  "issue_1691",
  "issue_1705",
@@ -32,15 +35,32 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
 [[package]]
 name = "getrandom"
 version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fc587bc0ec293155d5bfa6b9891ec18a1e330c234f896ea47fbada4cadbe47e6"
 dependencies = [
- "cfg-if",
+ "cfg-if 0.1.10",
  "libc",
- "wasi",
+ "wasi 0.9.0+wasi-snapshot-preview1",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c9495705279e7140bf035dde1f6e750c162df8b625267cd52cc44e0b156732c8"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "wasi 0.10.2+wasi-snapshot-preview1",
 ]
 
 [[package]]
@@ -116,7 +136,7 @@ version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
 dependencies = [
- "getrandom",
+ "getrandom 0.1.15",
  "libc",
  "rand_chacha",
  "rand_core",
@@ -140,7 +160,7 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
 dependencies = [
- "getrandom",
+ "getrandom 0.1.15",
 ]
 
 [[package]]
@@ -201,3 +221,9 @@ name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
+[[package]]
+name = "wasi"
+version = "0.10.2+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"

test-cargo-miri/Cargo.toml

@@ -16,6 +16,7 @@ issue_1705 = { path = "issue-1705" }
 
 [dev-dependencies]
 rand = { version = "0.7", features = ["small_rng"] }
+getrandom = { version = "0.2" }
 serde_derive = "1.0" # not actually used, but exercises some unique code path (`--extern` .so file)
 
 [lib]

test-cargo-miri/tests/test.rs

@@ -24,6 +24,10 @@ fn does_not_work_on_miri() {
 
 #[test]
 fn entropy_rng() {
+    // Test `getrandom` directly.
+    let mut data = vec![0; 16];
+    getrandom::getrandom(&mut data).unwrap();
+
     // Try seeding with "real" entropy.
     let mut rng = SmallRng::from_entropy();
     let _val = rng.gen::<i32>();