Fix unused and missing imports the batch's CI gate reported

Remove two unused imports and restore the json macro and resolve_alias
in test modules that the explicit import lists had dropped.

crates/engine/src/cmd/draw2/mline.rs

@@ -14,7 +14,7 @@ use super::super::machines::number;
 use super::super::ok;
 use super::curves::{self, MAX_GEN};
 use super::machines::number;
-use super::{CommandSpec, bad, bool_or, distinct_points, f64_or, line, ok, point_req, points_param, str_param};
+use super::{CommandSpec, bad, bool_or, distinct_points, f64_or, ok, point_req, points_param, str_param};
 
 use crate::{Accept, EngineError, Input, Interactive, Prompt, Result, Session, Step};
 

crates/engine/src/cmd/exchange.rs

@@ -18,7 +18,7 @@ use cadcraft_render::raster::{RasterOptions, View};
 use serde_json::{Value, json};
 
 use super::file::{base64_decode, base64_encode, io};
-use super::{CommandSpec, bad, point_value, resolve_alias, str_param};
+use super::{CommandSpec, bad, point_value, str_param};
 
 use crate::{EngineError, Result, Session};
 
@@ -558,7 +558,10 @@ mod tests {
     use cadcraft_geom::Vec3;
 
     use super::super::file::{IoHooks, set_io};
-    use super::{CommandSpec, bad, point_value, resolve_alias, str_param};
+
+    use super::super::resolve_alias;
+    use super::*;
+    use serde_json::json;
 
     static DELIVERED: std::sync::Mutex<Vec<(String, String, usize)>> = std::sync::Mutex::new(Vec::new());
 

crates/engine/src/cmd/file.rs

@@ -731,7 +731,8 @@ mod tests {
 
 #[cfg(test)]
 mod pr193_tests {
-    use super::{CommandSpec, EngineError, Interactive, bad, bool_or, ok, str_param};
+    use super::*;
+    use crate::Session;
 
     #[test]
     fn failed_store_keeps_unsaved_changes_and_delivered_save_clears_them() {