Simplify constant_time_test & remove its stdlib.h dependency.

Remove the trivial stdlib.h dependency from the test. Now the test
works more like other tests, so it's a double win.

crypto/constant_time_test.c

@@ -45,9 +45,6 @@
 
 #include "internal.h"
 
-#include <stdlib.h>
-
-
 int bssl_constant_time_test_main(void);
 
 static int test_binary_op_w(crypto_word (*op)(crypto_word a, crypto_word b),
@@ -127,9 +124,5 @@ int bssl_constant_time_test_main(void) {
     }
   }
 
-  if (!num_failed) {
-    return EXIT_SUCCESS;
-  }
-
-  return EXIT_FAILURE;
+  return num_failed == 0;
 }

src/bssl.rs

@@ -34,31 +34,6 @@ impl From<Result> for core::result::Result<(), error::Unspecified> {
     }
 }
 
-// Adapt a BoringSSL test suite to a Rust test.
-//
-// The BoringSSL test suite is broken up into multiple files. Originally, they
-// were all executables with their own `main` functions. Those main functions
-// have been replaced with uniquely-named functions so that they can all be
-// linked into the same executable.
-#[cfg(test)]
-macro_rules! bssl_test {
-    ( $fn_name:ident, $bssl_test_main_fn_name:ident ) => {
-        #[test]
-        fn $fn_name() {
-            use $crate::{c, cpu};
-            extern "C" {
-                #[must_use]
-                fn $bssl_test_main_fn_name() -> c::int;
-            }
-
-            let _ = cpu::features();
-
-            let result = unsafe { $bssl_test_main_fn_name() };
-            assert_eq!(result, 0);
-        }
-    };
-}
-
 #[cfg(test)]
 mod tests {
     mod result {

src/constant_time.rs

@@ -34,3 +34,16 @@ pub fn verify_slices_are_equal(a: &[u8], b: &[u8]) -> Result<(), error::Unspecif
 extern "C" {
     fn GFp_memcmp(a: *const u8, b: *const u8, len: c::size_t) -> c::int;
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{bssl, error};
+
+    #[test]
+    fn test_constant_time() -> Result<(), error::Unspecified> {
+        extern "C" {
+            fn bssl_constant_time_test_main() -> bssl::Result;
+        }
+        Result::from(unsafe { bssl_constant_time_test_main() })
+    }
+}

src/lib.rs

@@ -132,8 +132,3 @@ mod sealed {
     // ```
     pub trait Sealed {}
 }
-
-#[cfg(test)]
-mod tests {
-    bssl_test!(test_constant_time, bssl_constant_time_test_main);
-}