test: fix vacuous and weak assertions in ir/step.rs and ir/job.rs (#1070)

- job.rs / pool_variants_are_distinct: vacuous — different enum variants
  with #[derive(PartialEq)] are always unequal; renamed to
  pool_same_variant_different_values_are_not_equal and rewrote to test
  same-variant field discrimination (VmImage/Named with differing values
  are unequal; identical values are equal).

- step.rs / bash_step_builder_round_trip: weak — env.len()==1 only
  counts entries without verifying the stored key or value; added
  env.get("FOO") == Some(&EnvValue::literal("bar")) and
  outputs[0].name == "AW_OUT" to verify actual content.

- job.rs / new_starts_empty_depends_on_and_steps: incomplete — the
  analogous stage.rs test checks four fields; added condition.is_none(),
  variables.is_empty(), template_dependson_wrap.is_none(), and
  template_context.is_none() to match that coverage.

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

src/compile/ir/job.rs

@@ -211,14 +211,27 @@ mod tests {
     use super::*;
 
     #[test]
-    fn pool_variants_are_distinct() {
+    fn pool_same_variant_different_values_are_not_equal() {
+        // Equality semantics for same-variant: fields must match.
         let a = Pool::VmImage("ubuntu-22.04".into());
-        let b = Pool::Named {
-            name: "AZS-1ES-L".into(),
+        let b = Pool::VmImage("windows-2022".into());
+        assert_ne!(a, b, "different vmImage values should not be equal");
+
+        let c = Pool::Named {
+            name: "Pool-A".into(),
+            image: None,
+            os: None,
+        };
+        let d = Pool::Named {
+            name: "Pool-B".into(),
             image: None,
             os: None,
         };
-        assert_ne!(a, b);
+        assert_ne!(c, d, "different pool names should not be equal");
+
+        // Same values → equal.
+        let e = Pool::VmImage("ubuntu-22.04".into());
+        assert_eq!(a, e, "identical VmImage values should be equal");
     }
 
     #[test]
@@ -228,8 +241,18 @@ mod tests {
             "Agent",
             Pool::VmImage("ubuntu-22.04".into()),
         );
-        assert!(j.depends_on.is_empty());
-        assert!(j.steps.is_empty());
+        assert!(j.depends_on.is_empty(), "depends_on should start empty");
+        assert!(j.steps.is_empty(), "steps should start empty");
+        assert!(j.condition.is_none(), "condition should start as None");
+        assert!(j.variables.is_empty(), "variables should start empty");
+        assert!(
+            j.template_dependson_wrap.is_none(),
+            "template_dependson_wrap should start as None"
+        );
+        assert!(
+            j.template_context.is_none(),
+            "template_context should start as None"
+        );
     }
 
     #[test]

src/compile/ir/step.rs

@@ -238,8 +238,14 @@ mod tests {
         assert_eq!(s.display_name, "ado-aw");
         assert_eq!(s.script, "echo hi");
         assert_eq!(s.id.as_ref().map(|i| i.as_str()), Some("marker"));
-        assert_eq!(s.env.len(), 1);
-        assert_eq!(s.outputs.len(), 1);
+        // Verify the actual key and value were stored, not just the count.
+        assert_eq!(
+            s.env.get("FOO"),
+            Some(&EnvValue::literal("bar")),
+            "env should map FOO -> literal(\"bar\")"
+        );
+        assert_eq!(s.outputs.len(), 1, "should have exactly one output");
+        assert_eq!(s.outputs[0].name, "AW_OUT", "output name should be AW_OUT");
     }
 
     #[test]