Update test_harness clap args structure

Prepares it for adding a new subcommand

beacon_node/beacon_chain/test_harness/src/bin.rs

@@ -1,10 +1,9 @@
-use clap::{App, Arg};
+use clap::{App, Arg, SubCommand};
 use env_logger::{Builder, Env};
-use std::{fs::File, io::prelude::*};
+use run_test::run_test;
-use test_case::TestCase;
-use yaml_rust::YamlLoader;
 
 mod beacon_chain_harness;
+mod run_test;
 mod test_case;
 mod validator_harness;
 
@@ -15,13 +14,6 @@ fn main() {
         .version("0.0.1")
         .author("Sigma Prime <contact@sigmaprime.io>")
         .about("Runs `test_harness` using a YAML test_case.")
-        .arg(
-            Arg::with_name("yaml")
-                .long("yaml")
-                .value_name("FILE")
-                .help("YAML file test_case.")
-                .required(true),
-        )
         .arg(
             Arg::with_name("log")
                 .long("log-level")
@@ -31,39 +23,24 @@ fn main() {
                 .default_value("debug")
                 .required(true),
         )
+        .subcommand(
+            SubCommand::with_name("run_test")
+                .about("Executes a YAML test specification")
+                .arg(
+                    Arg::with_name("yaml")
+                        .long("yaml")
+                        .value_name("FILE")
+                        .help("YAML file test_case.")
+                        .required(true),
+                ),
+        )
         .get_matches();
 
     if let Some(log_level) = matches.value_of("log") {
         Builder::from_env(Env::default().default_filter_or(log_level)).init();
     }
 
-    if let Some(yaml_file) = matches.value_of("yaml") {
+    if let Some(matches) = matches.subcommand_matches("run_test") {
-        let docs = {
+        run_test(matches);
-            let mut file = File::open(yaml_file).unwrap();
-
-            let mut yaml_str = String::new();
-            file.read_to_string(&mut yaml_str).unwrap();
-
-            YamlLoader::load_from_str(&yaml_str).unwrap()
-        };
-
-        for doc in &docs {
-            // For each `test_cases` YAML in the document, build a `TestCase`, execute it and
-            // assert that the execution result matches the test_case description.
-            //
-            // In effect, for each `test_case` a new `BeaconChainHarness` is created from genesis
-            // and a new `BeaconChain` is built as per the test_case.
-            //
-            // After the `BeaconChain` has been built out as per the test_case, a dump of all blocks
-            // and states in the chain is obtained and checked against the `results` specified in
-            // the `test_case`.
-            //
-            // If any of the expectations in the results are not met, the process
-            // panics with a message.
-            for test_case in doc["test_cases"].as_vec().unwrap() {
-                let test_case = TestCase::from_yaml(test_case);
-                test_case.assert_result_valid(test_case.execute())
-            }
-        }
     }
 }

beacon_node/beacon_chain/test_harness/src/run_test.rs

@@ -0,0 +1,36 @@
+use crate::test_case::TestCase;
+use clap::ArgMatches;
+use std::{fs::File, io::prelude::*};
+use yaml_rust::YamlLoader;
+
+pub fn run_test(matches: &ArgMatches) {
+    if let Some(yaml_file) = matches.value_of("yaml") {
+        let docs = {
+            let mut file = File::open(yaml_file).unwrap();
+
+            let mut yaml_str = String::new();
+            file.read_to_string(&mut yaml_str).unwrap();
+
+            YamlLoader::load_from_str(&yaml_str).unwrap()
+        };
+
+        for doc in &docs {
+            // For each `test_cases` YAML in the document, build a `TestCase`, execute it and
+            // assert that the execution result matches the test_case description.
+            //
+            // In effect, for each `test_case` a new `BeaconChainHarness` is created from genesis
+            // and a new `BeaconChain` is built as per the test_case.
+            //
+            // After the `BeaconChain` has been built out as per the test_case, a dump of all blocks
+            // and states in the chain is obtained and checked against the `results` specified in
+            // the `test_case`.
+            //
+            // If any of the expectations in the results are not met, the process
+            // panics with a message.
+            for test_case in doc["test_cases"].as_vec().unwrap() {
+                let test_case = TestCase::from_yaml(test_case);
+                test_case.assert_result_valid(test_case.execute())
+            }
+        }
+    }
+}