Auto merge of rust-lang#2420 - RalfJung:num_cpus, r=RalfJung

move num_cpus test from test-cargo-miri to crate test

Author: bors

test-cargo-miri/Cargo.lock

@@ -18,4 +18,4 @@ path = "test.rs"
 harness = false
 
 [dev-dependencies]
-num_cpus = "1.10.1"
+byteorder = "1.0"

test-cargo-miri/subcrate/Cargo.toml

@@ -1,5 +1,7 @@
 use std::env;
 
+use byteorder::{ByteOrder, LittleEndian};
+
 fn main() {
     println!("subcrate testing");
 
@@ -11,6 +13,6 @@ fn main() {
     let crate_dir = crate_dir.to_string_lossy().replace("\\", "/");
     assert_eq!(env_dir, crate_dir);
 
-    // Make sure we can call `num_cpus`.
-    num_cpus::get();
+    // Make sure we can call dev-dependencies.
+    let _n = <LittleEndian as ByteOrder>::read_u32(&[1, 2, 3, 4]);
 }

test-cargo-miri/subcrate/test.rs

@@ -12,6 +12,7 @@ edition = "2021"
 tokio = { version = "1.0", features = ["full"] }
 libc = "0.2"
 page_size = "0.4.1"
+num_cpus = "1.10.1"
 
 getrandom_1 = { package = "getrandom", version = "0.1" }
 getrandom_2 = { package = "getrandom", version = "0.2" }

test_dependencies/Cargo.lock

@@ -0,0 +1,5 @@
+//@compile-flags: -Zmiri-disable-isolation
+
+fn main() {
+    assert_eq!(num_cpus::get(), 1);
+}

test_dependencies/Cargo.toml

@@ -1,6 +1,6 @@
-use rand::{rngs::SmallRng, Rng, SeedableRng};
 // mac-os `getrandom_1` does some pointer shenanigans
 //@compile-flags: -Zmiri-permissive-provenance
+use rand::{rngs::SmallRng, Rng, SeedableRng};
 
 fn main() {
     // Test `getrandom` directly (in multiple different versions).