Runtime benchmarks: start (#136)

* runtime benchmarks: start

* merge tests + benchmarks infrastructure

* fix compilation

* Fix compilation issues with runtime-benchmark feature flag

Mainly involved pulling in correct dependencies and adding some functions
which were called but didn't yet exist.

* Fix broken compilation for tests

* Move header signing methods into trait

* Move signing related test helpers to own module

* Remove comment about feature flag

* Add constants to tests

* Add top level comment for testing utilities

Co-authored-by: Hernando Castano <castano.ha@gmail.com>

bridges/modules/ethereum/Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 [dependencies]
 serde = { version = "1.0", optional = true }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false }
+hex-literal = "0.2"
 primitives = { package = "sp-bridge-eth-poa", path = "../../primitives/ethereum-poa", default-features = false }
 
 # Substrate Based Dependencies
@@ -41,21 +42,40 @@ default-features = false
 rev = "606c56d2e2f69f68f3947551224be6a3515dff60"
 git = "https://github.com/paritytech/substrate/"
 
+[dependencies.frame-benchmarking]
+optional = true
+version = "2.0.0-rc3"
+default-features = false
+rev = "606c56d2e2f69f68f3947551224be6a3515dff60"
+git = "https://github.com/paritytech/substrate/"
+
+[dependencies.libsecp256k1]
+optional = true
+version = "0.3.4"
+default-features = false
+features = ["hmac"]
+
 # Dev Dependencies
 [dev-dependencies]
 # TODO: Stop renaming this on import
 primitives = { package = "sp-bridge-eth-poa", path = "../../primitives/ethereum-poa", features = ["std", "test-helpers"] }
-parity-crypto = { version = "0.6", features = ["publickey"] }
+libsecp256k1 = { version = "0.3.4", features = ["hmac"] }
 
 [features]
 default = ["std"]
 std = [
-	"serde",
 	"codec/std",
-	"sp-std/std",
+	"frame-benchmarking/std",
 	"frame-support/std",
-	"sp-runtime/std",
 	"frame-system/std",
-	"sp-io/std",
 	"primitives/std",
+	"serde",
+	"sp-io/std",
+	"sp-runtime/std",
+	"sp-std/std",
+]
+runtime-benchmarks = [
+	"frame-benchmarking",
+	"libsecp256k1",
+	"primitives/test-helpers",
 ]