fix(c-bridge): properly read testnet environment config from envars

Author: guidiaz

bridges/centralized-ethereum/src/config.rs

@@ -126,10 +126,19 @@ pub fn from_file<S: AsRef<Path>>(file: S) -> Result<Config, Box<dyn std::error::
 /// Load configuration from environment variables
 pub fn from_env() -> Result<Config, envy::Error> {
     USING_ENVY.with(|x| x.set(true));
-    let res = envy::prefixed("WITNET_CENTRALIZED_ETHEREUM_BRIDGE_").from_env();
+    let res: Result<Config, envy::Error> = envy::prefixed("WITNET_CENTRALIZED_ETHEREUM_BRIDGE_").from_env();
     USING_ENVY.with(|x| x.set(false));
-
-    res
+    if let Ok(config) = res {
+        witnet_data_structures::set_environment(if config.witnet_testnet {
+            Environment::Testnet
+        } else {
+            Environment::Mainnet
+        });
+        Ok(config)
+    
+    } else {
+        res
+    }
 }
 
 thread_local! {

bridges/centralized-ethereum/src/main.rs

@@ -1,6 +1,7 @@
 //! Witnet <> Ethereum bridge
 
 use actix::{Actor, System, SystemRegistry};
+use witnet_data_structures::chain::Environment;
 use std::{path::PathBuf, process::exit, sync::Arc};
 use structopt::StructOpt;
 
@@ -59,9 +60,10 @@ fn main() {
 fn run(callback: fn()) -> Result<(), String> {
     let app = App::from_args();
     let config = if app.env {
-        config::from_env()
+        let config = config::from_env()
             .map(Arc::new)
-            .map_err(|e| format!("Error reading configuration from environment: {}", e))?
+            .map_err(|e| format!("Error reading configuration from environment: {}", e))?;
+        config
     } else {
         config::from_file(
             app.config