Directory Restructure (#1163)

* Move tests -> testing

* Directory restructure

* Update Cargo.toml during restructure

* Update Makefile during restructure

* Fix arbitrary path

common/eth2_config/src/lib.rs

@@ -0,0 +1,54 @@
+use serde_derive::{Deserialize, Serialize};
+use types::ChainSpec;
+
+/// The core configuration of a Lighthouse beacon node.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(default)]
+pub struct Eth2Config {
+    pub spec_constants: String,
+    pub spec: ChainSpec,
+}
+
+impl Default for Eth2Config {
+    fn default() -> Self {
+        Self {
+            spec_constants: "minimal".to_string(),
+            spec: ChainSpec::minimal(),
+        }
+    }
+}
+
+impl Eth2Config {
+    pub fn mainnet() -> Self {
+        Self {
+            spec_constants: "mainnet".to_string(),
+            spec: ChainSpec::mainnet(),
+        }
+    }
+
+    pub fn minimal() -> Self {
+        Self {
+            spec_constants: "minimal".to_string(),
+            spec: ChainSpec::minimal(),
+        }
+    }
+
+    pub fn interop() -> Self {
+        Self {
+            spec_constants: "interop".to_string(),
+            spec: ChainSpec::interop(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use toml;
+
+    #[test]
+    fn serde_serialize() {
+        let _ =
+            toml::to_string(&Eth2Config::default()).expect("Should serde encode default config");
+    }
+}