Add execute_with to TestExternalities (#3793)

This function executes the given closure in a context where the test
externalities are set. This makes the srml tests easier to write, as the
test externalities need to be created anyway.

substrate/core/sr-primitives/Cargo.toml

@@ -16,7 +16,6 @@ runtime_io = { package = "sr-io", path = "../sr-io", default-features = false }
 log = { version = "0.4.8", optional = true }
 paste = "0.1.6"
 rand = { version = "0.7.2", optional = true }
-externalities = { package = "substrate-externalities", path = "../externalities", optional = true }
 impl-trait-for-tuples = "0.1.2"
 
 [dev-dependencies]
@@ -38,5 +37,4 @@ std = [
 	"primitives/std",
 	"app-crypto/std",
 	"rand",
-	"externalities",
 ]

substrate/core/sr-primitives/src/lib.rs

@@ -73,9 +73,6 @@ pub use sr_arithmetic::helpers_128bit;
 /// Re-export big_uint stiff.
 pub use sr_arithmetic::biguint;
 
-#[cfg(feature = "std")]
-pub use externalities::set_and_run_with_externalities;
-
 /// An abstraction over justification for a block's validity under a consensus algorithm.
 ///
 /// Essentially a finality proof. The exact formulation will vary between consensus

substrate/core/sr-primitives/src/offchain/http.rs

@@ -512,7 +512,6 @@ impl<'a> HeadersIterator<'a> {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use crate::set_and_run_with_externalities;
 	use runtime_io::TestExternalities;
 	use substrate_offchain::testing;
 	use primitives::offchain::OffchainExt;
@@ -523,7 +522,7 @@ mod tests {
 		let mut t = TestExternalities::default();
 		t.register_extension(OffchainExt::new(offchain));
 
-		set_and_run_with_externalities(&mut t, || {
+		t.execute_with(|| {
 			let request: Request = Request::get("http://localhost:1234");
 			let pending = request
 				.add_header("X-Auth", "hunter2")
@@ -564,7 +563,7 @@ mod tests {
 		let mut t = TestExternalities::default();
 		t.register_extension(OffchainExt::new(offchain));
 
-		set_and_run_with_externalities(&mut t, || {
+		t.execute_with(|| {
 			let pending = Request::default()
 				.method(Method::Post)
 				.url("http://localhost:1234")