diff --git a/packages/catalog-client/api-report-testUtils.md b/packages/catalog-client/api-report-testUtils.md
index 47e917450c..3962cacce0 100644
--- a/packages/catalog-client/api-report-testUtils.md
+++ b/packages/catalog-client/api-report-testUtils.md
@@ -27,7 +27,9 @@ export class InMemoryCatalogClient implements CatalogApi {
   // (undocumented)
   addLocation(_location: AddLocationRequest): Promise<AddLocationResponse>;
   // (undocumented)
-  getEntities(_request?: GetEntitiesRequest): Promise<GetEntitiesResponse>;
+  getEntities(
+    request?: GetEntitiesRequest | undefined,
+  ): Promise<GetEntitiesResponse>;
   // (undocumented)
   getEntitiesByRefs(
     request: GetEntitiesByRefsRequest,
@@ -42,7 +44,7 @@ export class InMemoryCatalogClient implements CatalogApi {
   ): Promise<Entity | undefined>;
   // (undocumented)
   getEntityFacets(
-    _request: GetEntityFacetsRequest,
+    request: GetEntityFacetsRequest,
   ): Promise<GetEntityFacetsResponse>;
   // (undocumented)
   getLocationByEntity(
@@ -54,7 +56,7 @@ export class InMemoryCatalogClient implements CatalogApi {
   getLocationByRef(_locationRef: string): Promise<Location_2 | undefined>;
   // (undocumented)
   queryEntities(
-    _request?: QueryEntitiesRequest,
+    request?: QueryEntitiesRequest | undefined,
   ): Promise<QueryEntitiesResponse>;
   // (undocumented)
   refreshEntity(_entityRef: string): Promise<void>;
diff --git a/packages/catalog-client/src/testUtils/InMemoryCatalogClient.test.ts b/packages/catalog-client/src/testUtils/InMemoryCatalogClient.test.ts
index 0b5f0569bb..3f3eaed477 100644
--- a/packages/catalog-client/src/testUtils/InMemoryCatalogClient.test.ts
+++ b/packages/catalog-client/src/testUtils/InMemoryCatalogClient.test.ts
@@ -43,6 +43,9 @@ describe('InMemoryCatalogClient', () => {
   it('getEntities', async () => {
     const client = new InMemoryCatalogClient({ entities });
     await expect(client.getEntities()).resolves.toEqual({ items: entities });
+    await expect(
+      client.getEntities({ filter: { 'metadata.uid': 'u2' } }),
+    ).resolves.toEqual({ items: [entity2] });
   });
 
   it('getEntitiesByRefs', async () => {
@@ -56,6 +59,16 @@ describe('InMemoryCatalogClient', () => {
         ],
       }),
     ).resolves.toEqual({ items: [entity2, undefined, entity1] });
+    await expect(
+      client.getEntitiesByRefs({
+        entityRefs: [
+          'customkind:default/e2',
+          'customkind:missing/missing',
+          'customkind:default/e1',
+        ],
+        filter: { 'metadata.uid': 'u1' },
+      }),
+    ).resolves.toEqual({ items: [undefined, undefined, entity1] });
   });
 
   it('queryEntities', async () => {
@@ -65,6 +78,13 @@ describe('InMemoryCatalogClient', () => {
       totalItems: 2,
       pageInfo: {},
     });
+    await expect(
+      client.queryEntities({ filter: { 'metadata.uid': 'u2' } }),
+    ).resolves.toEqual({
+      items: [entity2],
+      totalItems: 1,
+      pageInfo: {},
+    });
   });
 
   it('getEntityAncestors', async () => {
diff --git a/packages/catalog-client/src/testUtils/InMemoryCatalogClient.ts b/packages/catalog-client/src/testUtils/InMemoryCatalogClient.ts
index a975a79b80..fc0c42bf52 100644
--- a/packages/catalog-client/src/testUtils/InMemoryCatalogClient.ts
+++ b/packages/catalog-client/src/testUtils/InMemoryCatalogClient.ts
@@ -46,17 +46,17 @@ function pick(obj: JsonObject, key: string): JsonValue | undefined {
   const parts = key.split('.');
 
   return parts.reduce((acc, part, index) => {
-    if (!acc) {
+    if (acc === undefined) {
       return acc;
     }
     if (typeof acc === 'object' && acc !== null && !Array.isArray(acc)) {
       const value = acc[part];
-      if (value) {
+      if (value !== undefined) {
         return value;
       }
       const rest = parts.slice(index).join('.');
       const restValue = acc[rest];
-      if (restValue) {
+      if (restValue !== undefined) {
         return restValue;
       }
     }
@@ -80,9 +80,8 @@ function createFilter(
   if (!filterOrFilters) {
     return () => true;
   }
-  const filters = Array.isArray(filterOrFilters)
-    ? filterOrFilters
-    : [filterOrFilters];
+
+  const filters = [filterOrFilters].flat();
 
   return entity => {
     return filters.some(filter => {
@@ -133,9 +132,13 @@ export class InMemoryCatalogClient implements CatalogApi {
   ): Promise<GetEntitiesByRefsResponse> {
     const filter = createFilter(request.filter);
     return {
-      items: request.entityRefs
-        .map(ref => this.#entitiesByRef.get(ref))
-        .filter(e => (e ? filter(e) : true)),
+      items: request.entityRefs.map(ref => {
+        const entity = this.#entitiesByRef.get(ref);
+        if (entity && filter(entity)) {
+          return entity;
+        }
+        return undefined;
+      }),
     };
   }
 
@@ -146,11 +149,12 @@ export class InMemoryCatalogClient implements CatalogApi {
       return { items: [], pageInfo: {}, totalItems: 0 };
     }
     const filter = createFilter(request?.filter);
+    const items = this.#entities.filter(filter);
     // TODO(Rugvip): Pagination
     return {
-      items: this.#entities.filter(filter),
+      items,
       pageInfo: {},
-      totalItems: this.#entities.length,
+      totalItems: items.length,
     };
   }
 
diff --git a/plugins/catalog-node/src/testUtils/catalogServiceMock.ts b/plugins/catalog-node/src/testUtils/catalogServiceMock.ts
index 5eeb704ff8..b9988572ac 100644
--- a/plugins/catalog-node/src/testUtils/catalogServiceMock.ts
+++ b/plugins/catalog-node/src/testUtils/catalogServiceMock.ts
@@ -23,6 +23,7 @@ import { Entity } from '@backstage/catalog-model';
 import { catalogServiceRef } from '@backstage/plugin-catalog-node/alpha';
 // eslint-disable-next-line @backstage/no-undeclared-imports
 import { ServiceMock } from '@backstage/backend-test-utils';
+import { CatalogApi } from '@backstage/catalog-client';
 
 /** @internal */
 function simpleMock<TService>(
@@ -57,7 +58,9 @@ function simpleMock<TService>(
  *
  * @public
  */
-export function catalogServiceMock(options?: { entities?: Entity[] }) {
+export function catalogServiceMock(options?: {
+  entities?: Entity[];
+}): CatalogApi {
   return new InMemoryCatalogClient(options);
 }