Spawn test node process for integration tests (#252)

* Move tests to module in own file

* Add test-node-proc crate

* Move test node to main lib, fix compilation errors

* Fmt

* Attempted port scanning

* Use global static port to allocate open ports

* Register missing type sizes

* Fix port scanning and balances test

* Don't wait for blocks on insert_jey test

* Fmt

* Remove unused dependencies

* Download v3.0.0 rust binary

* Move substrate bin to home dir

* Add test instructions to README

* Figure out the $PATH

* Remove path echo

* Add check for missing substrate binary on the PATH

* @niklasad1 review: don't include client feature for tests

src/rpc.rs

@@ -157,7 +157,7 @@ pub enum TransactionStatus<Hash, BlockHash> {
     Invalid,
 }
 
-#[cfg(any(feature = "client", test))]
+#[cfg(feature = "client")]
 use substrate_subxt_client::SubxtClient;
 
 /// Rpc client wrapper.
@@ -169,7 +169,7 @@ pub enum RpcClient {
     /// JSONRPC client HTTP transport.
     // NOTE: Arc because `HttpClient` is not clone.
     Http(Arc<HttpClient>),
-    #[cfg(any(feature = "client", test))]
+    #[cfg(feature = "client")]
     /// Embedded substrate node.
     Subxt(SubxtClient),
 }
@@ -186,7 +186,7 @@ impl RpcClient {
                 inner.request(method, params).await.map_err(Into::into)
             }
             Self::Http(inner) => inner.request(method, params).await.map_err(Into::into),
-            #[cfg(any(feature = "client", test))]
+            #[cfg(feature = "client")]
             Self::Subxt(inner) => inner.request(method, params).await.map_err(Into::into),
         }
     }
@@ -211,7 +211,7 @@ impl RpcClient {
                 )
                 .into())
             }
-            #[cfg(any(feature = "client", test))]
+            #[cfg(feature = "client")]
             Self::Subxt(inner) => {
                 inner
                     .subscribe(subscribe_method, params, unsubscribe_method)
@@ -234,7 +234,7 @@ impl From<HttpClient> for RpcClient {
     }
 }
 
-#[cfg(any(feature = "client", test))]
+#[cfg(feature = "client")]
 impl From<SubxtClient> for RpcClient {
     fn from(client: SubxtClient) -> Self {
         RpcClient::Subxt(client)