Use new interface

Signed-off-by: sblausten <sam@roadie.io>

plugins/tech-insights-backend/src/service/fact/FactRetrieverRegistry.ts

@@ -21,8 +21,17 @@ import {
 } from '@backstage/plugin-tech-insights-node';
 import { ConflictError, NotFoundError } from '@backstage/errors';
 
-export class FactRetrieverRegistry {
-  private readonly retrievers = new Map<string, FactRetrieverRegistration>();
+export interface FactRetrieverRegistryInterface {
+  readonly retrievers: Map<string, FactRetrieverRegistration>;
+  register(registration: FactRetrieverRegistration): void;
+  get(retrieverReference: string): FactRetrieverRegistration;
+  listRetrievers(): FactRetriever[];
+  listRegistrations(): FactRetrieverRegistration[];
+  getSchemas(): FactSchema[];
+}
+
+export class FactRetrieverRegistry implements FactRetrieverRegistryInterface {
+  readonly retrievers = new Map<string, FactRetrieverRegistration>();
 
   constructor(retrievers: FactRetrieverRegistration[]) {
     retrievers.forEach(it => {

plugins/tech-insights-backend/src/service/techInsightsContextBuilder.ts

@@ -16,7 +16,10 @@
 
 import { FactRetrieverEngine } from './fact/FactRetrieverEngine';
 import { Logger } from 'winston';
-import { FactRetrieverRegistry } from './fact/FactRetrieverRegistry';
+import {
+  FactRetrieverRegistry,
+  FactRetrieverRegistryInterface,
+} from './fact/FactRetrieverRegistry';
 import { Config } from '@backstage/config';
 import {
   PluginDatabaseManager,
@@ -59,7 +62,7 @@ export interface TechInsightsOptions<
    */
   factCheckerFactory?: FactCheckerFactory<CheckType, CheckResultType>;
 
-  factRetrieverRegistry?: FactRetrieverRegistry;
+  factRetrieverRegistry?: FactRetrieverRegistryInterface;
 
   logger: Logger;
   config: Config;
@@ -111,7 +114,7 @@ export const buildTechInsightsContext = async <
     tokenManager,
   } = options;
 
-  const buildFactRetrieverRegistry = () => {
+  const buildFactRetrieverRegistry = (): FactRetrieverRegistryInterface => {
     if (!options.factRetrieverRegistry) {
       if (!factRetrievers) {
         throw new Error(