feat(FN-3564): isolate plugin loader test state to prevent cross-test conta

Refactored plugin-loader tests and implementation to isolate plugin test contamination, improving test independence in `@fusion/core`.

Fusion-Task-Id: FN-3564

packages/engine/src/__tests__/plugin-runner.test.ts

@@ -34,6 +34,7 @@ describe("PluginRunner", () => {
     getPluginTools: ReturnType<typeof vi.fn>;
     getPluginRoutes: ReturnType<typeof vi.fn>;
     getPluginUiSlots: ReturnType<typeof vi.fn>;
+    getPluginUiContributions: ReturnType<typeof vi.fn>;
     getPluginRuntimes: ReturnType<typeof vi.fn>;
     getPluginSkills: ReturnType<typeof vi.fn>;
     getPluginWorkflowSteps: ReturnType<typeof vi.fn>;
@@ -94,6 +95,7 @@ describe("PluginRunner", () => {
       getPluginTools: vi.fn().mockReturnValue([]),
       getPluginRoutes: vi.fn().mockReturnValue([]),
       getPluginUiSlots: vi.fn().mockReturnValue([]),
+      getPluginUiContributions: vi.fn().mockReturnValue([]),
       getPluginRuntimes: vi.fn().mockReturnValue([]),
       getPluginSkills: vi.fn().mockReturnValue([]),
       getPluginWorkflowSteps: vi.fn().mockReturnValue([]),
@@ -534,6 +536,50 @@ describe("PluginRunner", () => {
     });
   });
 
+  describe("getPluginUiContributions()", () => {
+    it("returns structured contributions from pluginLoader", () => {
+      const contributions = [
+        {
+          pluginId: "plugin-a",
+          contribution: {
+            surface: "settings-config-section",
+            contributionId: "cfg-a",
+            sectionId: "openai",
+            title: "OpenAI settings",
+            pluginSettingKeys: ["openai.apiKey"],
+          },
+        },
+      ];
+      mockPluginLoader.getPluginUiContributions.mockReturnValue(contributions);
+
+      const result = pluginRunner.getPluginUiContributions();
+
+      expect(result).toEqual(contributions);
+      expect(mockPluginLoader.getPluginUiContributions).toHaveBeenCalledTimes(1);
+    });
+
+    it("uses cached contributions until invalidated", () => {
+      const contributions = [
+        {
+          pluginId: "plugin-a",
+          contribution: {
+            surface: "onboarding-provider-recommendation",
+            contributionId: "rec-a",
+            providerId: "openai",
+            title: "OpenAI",
+            reason: "default",
+          },
+        },
+      ];
+      mockPluginLoader.getPluginUiContributions.mockReturnValue(contributions);
+
+      pluginRunner.getPluginUiContributions();
+      pluginRunner.getPluginUiContributions();
+
+      expect(mockPluginLoader.getPluginUiContributions).toHaveBeenCalledTimes(1);
+    });
+  });
+
   describe("getPluginRuntimes()", () => {
     it("should return empty array when no plugins have runtimes", async () => {
       mockPluginLoader.getPluginRuntimes.mockReturnValue([]);

packages/engine/src/plugin-runner.ts

@@ -15,6 +15,7 @@ import type {
   PluginToolDefinition,
   PluginRouteDefinition,
   PluginUiSlotDefinition,
+  PluginUiContributionDefinition,
   PluginRuntimeRegistration,
   PluginContext,
   PluginSkillContribution,
@@ -68,6 +69,11 @@ interface CachedUiSlots {
   version: number;
 }
 
+interface CachedUiContributions {
+  contributions: Array<{ pluginId: string; contribution: PluginUiContributionDefinition }>;
+  version: number;
+}
+
 /**
  * Cached runtimes - rebuilt when plugin state changes
  */
@@ -112,6 +118,7 @@ export class PluginRunner {
   private cachedTools: CachedTools | null = null;
   private cachedRoutes: CachedRoutes | null = null;
   private cachedUiSlots: CachedUiSlots | null = null;
+  private cachedUiContributions: CachedUiContributions | null = null;
   private cachedRuntimes: CachedRuntimes | null = null;
   private cachedSkills: CachedSkills | null = null;
   private cachedWorkflowSteps: CachedWorkflowSteps | null = null;
@@ -121,6 +128,7 @@ export class PluginRunner {
   private toolsCacheVersion = 0;
   private routesCacheVersion = 0;
   private uiSlotsCacheVersion = 0;
+  private uiContributionsCacheVersion = 0;
   private runtimesCacheVersion = 0;
   private skillsCacheVersion = 0;
   private workflowStepsCacheVersion = 0;
@@ -196,6 +204,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -284,6 +293,16 @@ export class PluginRunner {
     return this.cachedUiSlots.slots;
   }
 
+  getPluginUiContributions(): Array<{ pluginId: string; contribution: PluginUiContributionDefinition }> {
+    if (!this.cachedUiContributions || this.cachedUiContributions.version !== this.uiContributionsCacheVersion) {
+      this.cachedUiContributions = {
+        contributions: this.options.pluginLoader.getPluginUiContributions(),
+        version: this.uiContributionsCacheVersion,
+      };
+    }
+    return this.cachedUiContributions.contributions;
+  }
+
   /**
    * Get all runtime registrations from loaded plugins.
    * Runtimes are cached and only rebuilt when plugin state changes.
@@ -404,6 +423,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -423,6 +443,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -447,6 +468,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -471,6 +493,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -494,6 +517,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -509,6 +533,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -524,6 +549,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -539,6 +565,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -554,6 +581,7 @@ export class PluginRunner {
     this.invalidateToolsCache();
     this.invalidateRoutesCache();
     this.invalidateUiSlotsCache();
+    this.invalidateUiContributionsCache();
     this.invalidateRuntimesCache();
     this.invalidateSkillsCache();
     this.invalidateWorkflowStepsCache();
@@ -757,6 +785,11 @@ export class PluginRunner {
     this.log.log(`UI slots cache invalidated (version: ${this.uiSlotsCacheVersion})`);
   }
 
+  private invalidateUiContributionsCache(): void {
+    this.uiContributionsCacheVersion++;
+    this.log.log(`UI contributions cache invalidated (version: ${this.uiContributionsCacheVersion})`);
+  }
+
   /**
    * Invalidate the runtimes cache, forcing rebuild on next access.
    */