fix(test-plans): use self-contained Maven fixture for resolve-unknown-type plan (#1617)

The plan previously pointed at redhat-developer/vscode-java's salut Maven fixture, which configures maven-compiler-plugin with <source>1.7</source>/<target>1.7</target>. On the CI runners (which install only JDK 21) this puts the workspace in a state where JDT reports compliance warnings on the pom but skips full semantic analysis on the Java source -- the inserted `Gson gson;` field never produces a `Gson cannot be resolved to a type` diagnostic, so navigateToError can never find the error and applyCodeAction `Resolve unknown type` is unreachable.

Older versions of @vscjava/vscode-autotest masked this failure mode by silently pressing Enter on whatever the first Code Action happened to be; once that fallback was removed upstream the plan started reliably failing in scheduled runs (e.g. actions/runs/25419116469).

Add a minimal self-owned Maven fixture under test-fixtures/maven-resolve-type that explicitly targets JDK 11 (<release>11</release>), matching the JDK installed by the workflow. Locally this brings navigateToError from a 30s timeout to ~8s and the full plan to 6/6 passing.

Co-authored-by: copilot <copilot@local>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 3 people

test-fixtures/maven-resolve-type/README.md

@@ -0,0 +1,16 @@
+# Maven Resolve Unknown Type — Test Fixture
+
+This fixture is consumed by `test-plans/java-maven-resolve-type.yaml`.
+
+It is a minimal self-contained Maven project intentionally configured with
+JDK 11 compliance (`<release>11</release>`), so JDT runs full semantic
+analysis under the JDK 21 toolchain that the E2E workflow installs. This
+avoids the historical problem of using fixtures with `<source>1.7</source>`,
+which causes JDT to emit only syntactic warnings (e.g. "compiler
+compliance 1.7 but JRE 11 is used") and silently skip semantic
+diagnostics — making the `Gson cannot be resolved to a type` error never
+surface and breaking the `Resolve unknown type` Code Action assertion.
+
+The plan inserts `Gson gson;` into `App.java`, expects JDT to publish the
+unresolved-type diagnostic, and then exercises `vscode-maven`'s
+`Resolve unknown type` Code Action.

test-fixtures/maven-resolve-type/pom.xml

@@ -0,0 +1,18 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.example</groupId>
+	<artifactId>maven-resolve-type</artifactId>
+	<version>1.0.0-SNAPSHOT</version>
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.8.0</version>
+				<configuration>
+					<release>11</release>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

test-fixtures/maven-resolve-type/src/main/java/com/example/App.java

@@ -0,0 +1,6 @@
+package com.example;
+
+public class App {
+    public static void main(String[] args) {
+    }
+}

test-plans/java-maven-resolve-type.yaml

@@ -4,11 +4,14 @@
 # Verify: Type unknown type → hover shows "Resolve unknown type" → add dependency and import
 #
 # Prerequisites:
-#   - vscode-java repo cloned locally
-#   - JDK installed and available
-#   - Maven installed
+#   - JDK 11+ installed and available on PATH (the workflow installs JDK 21)
+#   - Maven installed (or the redhat.java embedded one)
 #
 # Usage: autotest run test-plans/java-maven-resolve-type.yaml
+#
+# Fixture: test-fixtures/maven-resolve-type — self-contained, owned by this
+# repo. Uses JDK 11 compliance to ensure JDT runs full semantic analysis
+# and publishes the unresolved-type diagnostic (see fixture README).
 
 name: "Maven for Java — Resolve Unknown Type"
 description: |
@@ -21,7 +24,7 @@ setup:
   extensions:
     - "vscjava.vscode-java-pack"
   vscodeVersion: "stable"
-  workspace: "../../vscode-java/test/resources/projects/maven/salut"
+  workspace: "../test-fixtures/maven-resolve-type"
   timeout: 90
 
 steps:
@@ -32,20 +35,22 @@ steps:
     timeout: 120
 
   # ── Open Java file ──────────────────────────────────────
-  - id: "open-foo"
-    action: "open file Foo.java"
-    verify: "Foo.java file is open in the editor"
+  - id: "open-app"
+    action: "open file App.java"
+    verify: "App.java file is open in the editor"
     timeout: 15
 
   # ── Type unknown type ─────────────────────────────────────────
-  # wiki: "type 'Gson gson;'" — use insertLineInFile so LS detects the change
+  # wiki: "type 'Gson gson;'" — use insertLineInFile so LS detects the change.
+  # Line 4 places the field directly inside the class body of App.java.
   - id: "insert-unknown-type"
-    action: "insertLineInFile src/main/java/java/Foo.java 10         Gson gson;"
+    action: "insertLineInFile src/main/java/com/example/App.java 4         Gson gson;"
     waitBefore: 3
 
   # ── Verify Code Action: Resolve unknown type ────────────
-  # wiki: hover shows "Resolve unknown type" → apply Code Action
-  # Wait for LS to detect the Gson error before navigating
+  # wiki: hover shows "Resolve unknown type" → apply Code Action.
+  # navigateToError polls for diagnostics up to 30s and fails clearly if
+  # the LS hasn't published the unresolved-type error yet.
   - id: "navigate-to-error"
     action: "navigateToError 1"
     waitBefore: 5