diff --git a/src/extensions/lens-main-extension.test.ts b/src/extensions/lens-main-extension.test.ts
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+++ b/src/extensions/lens-main-extension.test.ts
@@ -0,0 +1,181 @@
+/**
+ * Copyright (c) 2021 OpenLens Authors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+import { observable, reaction } from "mobx";
+import { WebLink, WebLinkSpec, WebLinkStatus } from "../common/catalog-entities";
+import { CatalogEntity, CatalogEntityMetadata } from "../common/catalog";
+import { LensMainExtension } from "./lens-main-extension";
+import { catalogEntityRegistry } from "../main/catalog";
+
+class InvalidEntity extends CatalogEntity<CatalogEntityMetadata, WebLinkStatus, WebLinkSpec> {
+   public readonly apiVersion = "entity.k8slens.dev/v1alpha1";
+   public readonly kind = "Invalid";
+ 
+   async onRun() {
+     return;
+   }
+ 
+   public onSettingsOpen(): void {
+     return;
+   }
+ 
+   public onDetailsOpen(): void {
+     return;
+   }
+ 
+   public onContextMenuOpen(): void {
+     return;
+   }
+}
+ 
+describe("LensMainExtension", () => {
+  let lensMainExtension: LensMainExtension;
+  const entity = new WebLink({
+    metadata: {
+      uid: "test",
+      name: "test-link",
+      source: "test",
+      labels: {}
+    },
+    spec: {
+      url: "https://k8slens.dev"
+    },
+    status: {
+      phase: "available"
+    }
+  });
+  const invalidEntity = new InvalidEntity({
+    metadata: {
+      uid: "invalid",
+      name: "test-link",
+      source: "test",
+      labels: {}
+    },
+    spec: {
+      url: "https://k8slens.dev"
+    },
+    status: {
+      phase: "available"
+    }
+  });
+ 
+  beforeEach(() => {
+    lensMainExtension = new LensMainExtension({
+      id: "lens-main-extension-test",
+      absolutePath: "",
+      manifestPath: "",
+      isBundled: false,
+      isCompatible: true,
+      isEnabled: true,
+      manifest: {
+        name: "",
+        version: "",
+      },
+    });
+  });
+ 
+  describe("LensMainExtension.addCatalogSource", () => {
+    it ("allows to add an observable source", () => {
+      const source = observable.array([]);
+ 
+      lensMainExtension.addCatalogSource("test", source);
+      expect(catalogEntityRegistry.items.length).toEqual(0);
+ 
+      source.push(entity);
+ 
+      expect(catalogEntityRegistry.items.length).toEqual(1);
+    });
+ 
+    it ("can mutate entity", () => {
+      const source = observable.array([]);
+ 
+      lensMainExtension.addCatalogSource("test", source);
+      source.push(entity);
+       
+      const index = source.findIndex((i) => i.metadata.uid === entity.metadata.uid);
+ 
+      const updateEntity = new WebLink({
+        metadata: {
+          uid: "test",
+          name: "test-link",
+          source: "test",
+          labels: {}
+        },
+        spec: {
+          url: "https://k8slens.dev"
+        },
+        status: {
+          phase: "unavailable"
+        }
+      });
+ 
+      source.splice(index, 1, updateEntity);
+      expect(catalogEntityRegistry.items.length).toEqual(1);
+ 
+      const found = catalogEntityRegistry.items.find((i) => i.metadata.uid === updateEntity.metadata.uid);
+ 
+      expect(found).toBeDefined();
+      expect(found.status.phase).toBe("unavailable");
+    });
+ 
+    it ("added source change triggers reaction", (done) => {
+      const source = observable.array([]);
+ 
+      lensMainExtension.addCatalogSource("test", source);
+      reaction(() => catalogEntityRegistry.items, () => {
+        done();
+      });
+ 
+      source.push(entity);
+    });
+  });
+ 
+  describe("LensMainExtension.removeCatalogSource", () => {
+    it ("removes source", () => {
+      const source = observable.array([]);
+ 
+      lensMainExtension.addCatalogSource("test", source);
+      source.push(entity);
+      lensMainExtension.removeCatalogSource("test");
+ 
+      expect(catalogEntityRegistry.items.length).toEqual(0);
+    });
+  });
+ 
+  describe("items", () => {
+    it("returns added items", () => {
+      expect(catalogEntityRegistry.items.length).toBe(0);
+ 
+      const source = observable.array([entity]);
+ 
+      lensMainExtension.addCatalogSource("test", source);
+      expect(catalogEntityRegistry.items.length).toBe(1);
+    });
+ 
+    it("does not return items without matching category", () => {
+      const source = observable.array([invalidEntity]);
+ 
+      lensMainExtension.addCatalogSource("test", source);
+      expect(catalogEntityRegistry.items.length).toBe(0);
+    });
+  });
+});
+