Don't parse arguments during cargo test (#37)

Otherwise, running the tests with special arguments (e.g. `cargo test --
--test-threads 1`) will break.

src/main.rs

@@ -36,10 +36,21 @@ struct Configuration {
     input: String,
 }
 
+#[cfg(not(test))]
 lazy_static! {
     static ref CONFIGURATION: Configuration = parse_arguments();
 }
 
+#[cfg(test)]
+lazy_static! {
+    static ref CONFIGURATION: Configuration = Configuration {
+        radian_mode: false,
+        fix: 10,
+        base: 10,
+        input: "".to_string(),
+    };
+}
+
 fn main() {
     if !CONFIGURATION.input.is_empty() {
         // command mode //