fix(run): run JUnit configurations with the build's JDK

crates/ide-host/src/ops/run.rs

@@ -337,7 +337,7 @@ async fn start_inner(
     // what makes the setting take effect without reopening the project.
     if config.kind == "maven" {
         ide_sdk::apply::prepare_maven_run(&mut config, root, &settings);
-    } else if matches!(config.kind.as_str(), "gradle" | "tomcat") {
+    } else if matches!(config.kind.as_str(), "gradle" | "tomcat" | "junit") {
         ide_sdk::apply::apply_to_run_configs(std::slice::from_mut(&mut config), root, &settings);
     } else {
         ide_sdk::apply::resolve_run_command(&mut config, root, &settings);

crates/ide-sdk/src/apply.rs

@@ -1561,6 +1561,24 @@ pub fn apply_to_run_configs(configs: &mut [RunConfig], root: &Path, s: &Settings
                     c.env.entry("JAVA_HOME".into()).or_insert_with(|| jdk.home.to_string_lossy().into_owned());
                 }
             }
+            // A JUnit configuration runs the module's own Maven or Gradle command line: it needs
+            // that build's environment (its JDK), not another launcher or extra options.
+            "junit" => {
+                let name = Path::new(&c.command).file_name().map(|n| n.to_string_lossy().to_ascii_lowercase());
+                match name.as_deref() {
+                    Some(n) if n.starts_with("mvn") => apply_maven_env(c, root, s),
+                    Some(n) if n.starts_with("gradle") => {
+                        let build_dir =
+                            c.cwd.as_ref().map(|p| root.join(p.as_ref())).unwrap_or_else(|| root.to_path_buf());
+                        let env = gradle_build_env(root, &build_dir, &c.command, s, None);
+                        apply_java_home(c, &env, java_home_is_derived(c));
+                        for (key, value) in env {
+                            c.env.entry(key).or_insert(value);
+                        }
+                    }
+                    _ => {}
+                }
+            }
             "maven" => {
                 apply_maven_env(c, root, s);
                 if let Some(mvn) = &mvn

crates/ide-sdk/src/tests.rs

@@ -409,6 +409,19 @@ fn project_jdk_and_maven_settings() {
     );
     assert_eq!(configs[0].env["JAVA_HOME"], home);
     assert_eq!(configs[1].env["JAVA_HOME"], home);
+    // JUnit runs the build's own command line: the build's JDK, its command and arguments unchanged.
+    let mut junit = vec![
+        run("junit", "./mvnw", &["test", "-Dtest=a.T"]),
+        run("junit", "./gradlew", &[":api:test", "--tests", "a.T"]),
+    ];
+    apply_to_run_configs(&mut junit, tmp.path(), &s);
+    assert_eq!(
+        (junit[0].command.as_str(), junit[0].args.as_slice()),
+        ("./mvnw", &["test".to_owned(), "-Dtest=a.T".to_owned()][..])
+    );
+    assert_eq!(junit[0].env["JAVA_HOME"], home);
+    assert_eq!(junit[1].command, "./gradlew");
+    assert_eq!(junit[1].env["JAVA_HOME"], home);
     apply_to_run_configs(&mut configs, tmp.path(), &s);
     assert_eq!(configs[0].args.len(), 6, "applied once");