From cdda9c671d500c26a58759d276d3cd9b4591a6ac Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Fri, 23 Apr 2021 15:03:32 +0200
Subject: [PATCH 01/13] move refresh loop to builder and use configured
 refreshInterval

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 packages/backend/src/plugins/search.ts        |  7 +---
 .../search-backend-node/src/IndexBuilder.ts   | 37 ++++++++++---------
 2 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/packages/backend/src/plugins/search.ts b/packages/backend/src/plugins/search.ts
index a980661c85..da7ee193b4 100644
--- a/packages/backend/src/plugins/search.ts
+++ b/packages/backend/src/plugins/search.ts
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { useHotCleanup } from '@backstage/backend-common';
 import { createRouter } from '@backstage/plugin-search-backend';
 import {
   IndexBuilder,
@@ -35,11 +34,7 @@ export default async function createPlugin({
     collator: new DefaultCatalogCollator(discovery),
   });
 
-  // TODO: Move refresh loop logic into the builder.
-  const timerId = setInterval(() => {
-    indexBuilder.build();
-  }, 60000);
-  useHotCleanup(module, () => clearInterval(timerId));
+  indexBuilder.build();
 
   return await createRouter({
     engine: indexBuilder.getSearchEngine(),
diff --git a/plugins/search-backend-node/src/IndexBuilder.ts b/plugins/search-backend-node/src/IndexBuilder.ts
index 0f5a287037..199cb7f923 100644
--- a/plugins/search-backend-node/src/IndexBuilder.ts
+++ b/plugins/search-backend-node/src/IndexBuilder.ts
@@ -100,28 +100,31 @@ export class IndexBuilder {
   async build() {
     return Promise.all(
       Object.keys(this.collators).map(async type => {
-        const decorators: DocumentDecorator[] = (
-          this.decorators['*'] || []
-        ).concat(this.decorators[type] || []);
+        setInterval(async () => {
+          const decorators: DocumentDecorator[] = (
+            this.decorators['*'] || []
+          ).concat(this.decorators[type] || []);
 
-        this.logger.info(
-          `Collating documents for ${type} via ${this.collators[type].collate.constructor.name}`,
-        );
-        let documents = await this.collators[type].collate.execute();
-        for (let i = 0; i < decorators.length; i++) {
           this.logger.info(
-            `Decorating ${type} documents via ${decorators[i].constructor.name}`,
+            `Collating documents for ${type} via ${this.collators[type].collate.constructor.name}`,
           );
-          documents = await decorators[i].execute(documents);
-        }
+          let documents = await this.collators[type].collate.execute();
+          for (let i = 0; i < decorators.length; i++) {
+            this.logger.info(
+              `Decorating ${type} documents via ${decorators[i].constructor.name}`,
+            );
+            documents = await decorators[i].execute(documents);
+          }
 
-        if (!documents || documents.length === 0) {
-          this.logger.info(`No documents for type "${type}" to index`);
-          return;
-        }
+          if (!documents || documents.length === 0) {
+            this.logger.info(`No documents for type "${type}" to index`);
+            return;
+          }
 
-        // pushing documents to index to a configured search engine.
-        this.searchEngine.index(type, documents);
+          // pushing documents to index to a configured search engine.
+          this.searchEngine.index(type, documents);
+          // refreshInterval configured in seconds, setInterval want milliseconds
+        }, this.collators[type].refreshInterval * 1000);
       }),
     );
   }

From f5ba99d61c5acc77b2bc7b6cc0dad0d2a6796993 Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Fri, 23 Apr 2021 15:07:12 +0200
Subject: [PATCH 02/13] add changeset

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 .changeset/odd-ads-invite.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/odd-ads-invite.md

diff --git a/.changeset/odd-ads-invite.md b/.changeset/odd-ads-invite.md
new file mode 100644
index 0000000000..d487df47d3
--- /dev/null
+++ b/.changeset/odd-ads-invite.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-search-backend-node': patch
+---
+
+Moved refresh loop to builder and use configured refreshInterval for each collator

From 8c0184a1c8858e1bc1673438ae44e0f4b94f019e Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 13:37:27 +0200
Subject: [PATCH 03/13] use timers in tests

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 plugins/search-backend-node/src/index.test.ts | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/plugins/search-backend-node/src/index.test.ts b/plugins/search-backend-node/src/index.test.ts
index 0c66db372a..86233425e7 100644
--- a/plugins/search-backend-node/src/index.test.ts
+++ b/plugins/search-backend-node/src/index.test.ts
@@ -54,29 +54,32 @@ describe('IndexBuilder', () => {
 
   describe('addCollator', () => {
     it('adds a collator', async () => {
+      jest.useFakeTimers();
       const collatorSpy = jest.spyOn(testCollator, 'execute');
 
       // Add a collator.
       testIndexBuilder.addCollator({
         type: 'anything',
-        defaultRefreshIntervalSeconds: 600,
+        defaultRefreshIntervalSeconds: 6,
         collator: testCollator,
       });
 
       // Build the index and ensure the collator was invoked.
       await testIndexBuilder.build();
+      jest.advanceTimersByTime(6000);
       expect(collatorSpy).toHaveBeenCalled();
     });
   });
 
   describe('addDecorator', () => {
     it('adds a decorator', async () => {
+      jest.useFakeTimers();
       const decoratorSpy = jest.spyOn(testDecorator, 'execute');
 
       // Add a collator.
       testIndexBuilder.addCollator({
         type: 'anything',
-        defaultRefreshIntervalSeconds: 600,
+        defaultRefreshIntervalSeconds: 6,
         collator: testCollator,
       });
 
@@ -87,10 +90,14 @@ describe('IndexBuilder', () => {
 
       // Build the index and ensure the decorator was invoked.
       await testIndexBuilder.build();
+      jest.advanceTimersByTime(6000);
+      // wait for async decorator execution
+      await Promise.resolve();
       expect(decoratorSpy).toHaveBeenCalled();
     });
 
     it('adds a type-specific decorator', async () => {
+      jest.useFakeTimers();
       const expectedType = 'an-expected-type';
       const docFixture = {
         title: 'Test',
@@ -105,7 +112,7 @@ describe('IndexBuilder', () => {
       // Add a collator.
       testIndexBuilder.addCollator({
         type: expectedType,
-        defaultRefreshIntervalSeconds: 600,
+        defaultRefreshIntervalSeconds: 6,
         collator: testCollator,
       });
 
@@ -117,6 +124,9 @@ describe('IndexBuilder', () => {
 
       // Build the index and ensure the decorator was invoked.
       await testIndexBuilder.build();
+      jest.advanceTimersByTime(6000);
+      // wait for async decorator execution
+      await Promise.resolve();
       expect(decoratorSpy).toHaveBeenCalled();
       expect(decoratorSpy).toHaveBeenCalledWith([docFixture]);
     });
@@ -136,7 +146,7 @@ describe('IndexBuilder', () => {
       // Add a collator.
       testIndexBuilder.addCollator({
         type: expectedType,
-        defaultRefreshIntervalSeconds: 600,
+        defaultRefreshIntervalSeconds: 6,
         collator: testCollator,
       });
 
@@ -148,6 +158,7 @@ describe('IndexBuilder', () => {
 
       // Build the index and ensure the decorator was not invoked.
       await testIndexBuilder.build();
+      jest.advanceTimersByTime(6000);
       expect(decoratorSpy).not.toHaveBeenCalled();
     });
   });

From 1c2d8436ab1af5c5424d78b8c5ac04647b3e24fe Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 13:38:15 +0200
Subject: [PATCH 04/13] change log severity from info to debug

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 plugins/search-backend-node/src/IndexBuilder.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/plugins/search-backend-node/src/IndexBuilder.ts b/plugins/search-backend-node/src/IndexBuilder.ts
index 199cb7f923..0fc881c262 100644
--- a/plugins/search-backend-node/src/IndexBuilder.ts
+++ b/plugins/search-backend-node/src/IndexBuilder.ts
@@ -105,19 +105,19 @@ export class IndexBuilder {
             this.decorators['*'] || []
           ).concat(this.decorators[type] || []);
 
-          this.logger.info(
+          this.logger.debug(
             `Collating documents for ${type} via ${this.collators[type].collate.constructor.name}`,
           );
           let documents = await this.collators[type].collate.execute();
           for (let i = 0; i < decorators.length; i++) {
-            this.logger.info(
+            this.logger.debug(
               `Decorating ${type} documents via ${decorators[i].constructor.name}`,
             );
             documents = await decorators[i].execute(documents);
           }
 
           if (!documents || documents.length === 0) {
-            this.logger.info(`No documents for type "${type}" to index`);
+            this.logger.debug(`No documents for type "${type}" to index`);
             return;
           }
 

From da489d2cd3a29f30749829e804ff8f9668153e0f Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 16:38:34 +0200
Subject: [PATCH 05/13] add new Scheduler Class

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 plugins/search-backend-node/src/Scheduler.ts | 75 ++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 plugins/search-backend-node/src/Scheduler.ts

diff --git a/plugins/search-backend-node/src/Scheduler.ts b/plugins/search-backend-node/src/Scheduler.ts
new file mode 100644
index 0000000000..e54a837cee
--- /dev/null
+++ b/plugins/search-backend-node/src/Scheduler.ts
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Logger } from 'winston';
+
+type TaskEnvelope = {
+  task: Function;
+  interval: number;
+};
+
+/**
+ * TODO: coordination, error handling
+ */
+
+export class Scheduler {
+  private logger: Logger;
+  private schedule: TaskEnvelope[];
+  private intervalTimeouts: NodeJS.Timeout[] = [];
+
+  constructor({ logger }: { logger: Logger }) {
+    this.logger = logger;
+    this.schedule = [];
+  }
+
+  /**
+   * Adds each task and interval to the schedule
+   *
+   */
+  addToSchedule(task: Function, interval: number) {
+    if (this.intervalTimeouts.length) {
+      throw new Error(
+        'Cannot add task to schedule that has already been started.',
+      );
+    }
+    this.schedule.push({ task, interval });
+  }
+
+  /**
+   * Starts the scheduling process for each task
+   */
+  start() {
+    this.logger.info('Starting all scheduled search tasks.');
+    this.schedule.forEach(({ task, interval }) => {
+      this.intervalTimeouts.push(
+        setInterval(() => {
+          task();
+        }, interval),
+      );
+    });
+  }
+
+  /**
+   * Stop all scheduled tasks.
+   */
+  stop() {
+    this.logger.info('Stopping all scheduled search tasks.');
+    this.intervalTimeouts.forEach(timeout => {
+      clearInterval(timeout);
+    });
+    this.intervalTimeouts = [];
+  }
+}

From 0b9eac3a819e3185c98a339124871f85fb2383e8 Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 16:39:33 +0200
Subject: [PATCH 06/13] refactor build method in indexBuilder

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 .../search-backend-node/src/IndexBuilder.ts   | 62 ++++++++++---------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/plugins/search-backend-node/src/IndexBuilder.ts b/plugins/search-backend-node/src/IndexBuilder.ts
index 0fc881c262..768dee5b67 100644
--- a/plugins/search-backend-node/src/IndexBuilder.ts
+++ b/plugins/search-backend-node/src/IndexBuilder.ts
@@ -16,7 +16,7 @@
 
 import { DocumentCollator, DocumentDecorator } from '@backstage/search-common';
 import { Logger } from 'winston';
-
+import { Scheduler } from './index';
 import {
   RegisterCollatorParameters,
   RegisterDecoratorParameters,
@@ -92,40 +92,42 @@ export class IndexBuilder {
   }
 
   /**
-   * Starts the process of executing collators and decorators and building the
-   * search index.
-   *
-   * TODO: But like with coordination, timing, error handling, and what have you.
+   * Compiles collators and decorators into tasks, which are added to a
+   * scheduler returned to the caller.
    */
-  async build() {
-    return Promise.all(
-      Object.keys(this.collators).map(async type => {
-        setInterval(async () => {
-          const decorators: DocumentDecorator[] = (
-            this.decorators['*'] || []
-          ).concat(this.decorators[type] || []);
+  async build(): Promise<{ scheduler: Scheduler }> {
+    const scheduler = new Scheduler({ logger: this.logger });
 
+    Object.keys(this.collators).map(type => {
+      scheduler.addToSchedule(async () => {
+        // Collate, Decorate, Index.
+        const decorators: DocumentDecorator[] = (
+          this.decorators['*'] || []
+        ).concat(this.decorators[type] || []);
+
+        this.logger.debug(
+          `Collating documents for ${type} via ${this.collators[type].collate.constructor.name}`,
+        );
+        let documents = await this.collators[type].collate.execute();
+        for (let i = 0; i < decorators.length; i++) {
           this.logger.debug(
-            `Collating documents for ${type} via ${this.collators[type].collate.constructor.name}`,
+            `Decorating ${type} documents via ${decorators[i].constructor.name}`,
           );
-          let documents = await this.collators[type].collate.execute();
-          for (let i = 0; i < decorators.length; i++) {
-            this.logger.debug(
-              `Decorating ${type} documents via ${decorators[i].constructor.name}`,
-            );
-            documents = await decorators[i].execute(documents);
-          }
+          documents = await decorators[i].execute(documents);
+        }
 
-          if (!documents || documents.length === 0) {
-            this.logger.debug(`No documents for type "${type}" to index`);
-            return;
-          }
+        if (!documents || documents.length === 0) {
+          this.logger.debug(`No documents for type "${type}" to index`);
+          return;
+        }
 
-          // pushing documents to index to a configured search engine.
-          this.searchEngine.index(type, documents);
-          // refreshInterval configured in seconds, setInterval want milliseconds
-        }, this.collators[type].refreshInterval * 1000);
-      }),
-    );
+        // pushing documents to index to a configured search engine.
+        this.searchEngine.index(type, documents);
+      }, this.collators[type].refreshInterval * 1000);
+    });
+
+    return {
+      scheduler,
+    };
   }
 }

From 9dff1a9839704af0ae722372a728b504ebe27bec Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 16:43:58 +0200
Subject: [PATCH 07/13] use scheduler and fix tests

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 packages/backend/src/plugins/search.ts        |  5 ++++-
 plugins/search-backend-node/src/index.test.ts | 15 ++++++++++-----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/packages/backend/src/plugins/search.ts b/packages/backend/src/plugins/search.ts
index da7ee193b4..03c7d44a18 100644
--- a/packages/backend/src/plugins/search.ts
+++ b/packages/backend/src/plugins/search.ts
@@ -34,7 +34,10 @@ export default async function createPlugin({
     collator: new DefaultCatalogCollator(discovery),
   });
 
-  indexBuilder.build();
+  const { scheduler } = await indexBuilder.build();
+
+  scheduler.start();
+  useHotCleanup(module, () => scheduler.stop());
 
   return await createRouter({
     engine: indexBuilder.getSearchEngine(),
diff --git a/plugins/search-backend-node/src/index.test.ts b/plugins/search-backend-node/src/index.test.ts
index 86233425e7..e1dc511b97 100644
--- a/plugins/search-backend-node/src/index.test.ts
+++ b/plugins/search-backend-node/src/index.test.ts
@@ -65,7 +65,8 @@ describe('IndexBuilder', () => {
       });
 
       // Build the index and ensure the collator was invoked.
-      await testIndexBuilder.build();
+      const { scheduler } = await testIndexBuilder.build();
+      scheduler.start();
       jest.advanceTimersByTime(6000);
       expect(collatorSpy).toHaveBeenCalled();
     });
@@ -89,7 +90,8 @@ describe('IndexBuilder', () => {
       });
 
       // Build the index and ensure the decorator was invoked.
-      await testIndexBuilder.build();
+      const { scheduler } = await testIndexBuilder.build();
+      scheduler.start();
       jest.advanceTimersByTime(6000);
       // wait for async decorator execution
       await Promise.resolve();
@@ -123,7 +125,8 @@ describe('IndexBuilder', () => {
       });
 
       // Build the index and ensure the decorator was invoked.
-      await testIndexBuilder.build();
+      const { scheduler } = await testIndexBuilder.build();
+      scheduler.start();
       jest.advanceTimersByTime(6000);
       // wait for async decorator execution
       await Promise.resolve();
@@ -138,7 +141,7 @@ describe('IndexBuilder', () => {
         text: 'Test text.',
         location: '/test/location',
       };
-      jest
+      const collatorSpy = jest
         .spyOn(testCollator, 'execute')
         .mockImplementation(async () => [docFixture]);
       const decoratorSpy = jest.spyOn(testDecorator, 'execute');
@@ -157,8 +160,10 @@ describe('IndexBuilder', () => {
       });
 
       // Build the index and ensure the decorator was not invoked.
-      await testIndexBuilder.build();
+      const { scheduler } = await testIndexBuilder.build();
+      scheduler.start();
       jest.advanceTimersByTime(6000);
+      expect(collatorSpy).toHaveBeenCalled();
       expect(decoratorSpy).not.toHaveBeenCalled();
     });
   });

From 50b15bfeb3495f623f0bce521ad9e5d5b383951d Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 16:44:32 +0200
Subject: [PATCH 08/13] imports and exports

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 packages/backend/src/plugins/search.ts   | 1 +
 plugins/search-backend-node/src/index.ts | 1 +
 2 files changed, 2 insertions(+)

diff --git a/packages/backend/src/plugins/search.ts b/packages/backend/src/plugins/search.ts
index 03c7d44a18..dcd48aaf40 100644
--- a/packages/backend/src/plugins/search.ts
+++ b/packages/backend/src/plugins/search.ts
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+import { useHotCleanup } from '@backstage/backend-common';
 import { createRouter } from '@backstage/plugin-search-backend';
 import {
   IndexBuilder,
diff --git a/plugins/search-backend-node/src/index.ts b/plugins/search-backend-node/src/index.ts
index a3a0eb855e..7ee75e3d59 100644
--- a/plugins/search-backend-node/src/index.ts
+++ b/plugins/search-backend-node/src/index.ts
@@ -15,5 +15,6 @@
  */
 
 export { IndexBuilder } from './IndexBuilder';
+export { Scheduler } from './Scheduler';
 export { LunrSearchEngine } from './engines';
 export type { SearchEngine } from './types';

From fafd8043649dd7432bde654eaee11cf58539544f Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 16:49:32 +0200
Subject: [PATCH 09/13] update changeset

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 .changeset/odd-ads-invite.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.changeset/odd-ads-invite.md b/.changeset/odd-ads-invite.md
index d487df47d3..0dde3d0c1f 100644
--- a/.changeset/odd-ads-invite.md
+++ b/.changeset/odd-ads-invite.md
@@ -2,4 +2,4 @@
 '@backstage/plugin-search-backend-node': patch
 ---
 
-Moved refresh loop to builder and use configured refreshInterval for each collator
+Introduced Scheduler which is responsible for adding new tasks to a schedule together with it's interval timer as well as starting and stopping the scheduler processes.

From e1e757569fbb2f3b9b30ab48229ec2ef97cc0c7f Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Mon, 26 Apr 2021 17:32:54 +0200
Subject: [PATCH 10/13] prefix changeset with search

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 .changeset/{odd-ads-invite.md => search-odd-ads-invite.md} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename .changeset/{odd-ads-invite.md => search-odd-ads-invite.md} (100%)

diff --git a/.changeset/odd-ads-invite.md b/.changeset/search-odd-ads-invite.md
similarity index 100%
rename from .changeset/odd-ads-invite.md
rename to .changeset/search-odd-ads-invite.md

From 266e46d3c3a4f73f5c27f50c4275be254b4ed9e9 Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Tue, 27 Apr 2021 11:07:08 +0200
Subject: [PATCH 11/13] switch from map to forEach

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 plugins/search-backend-node/src/IndexBuilder.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/search-backend-node/src/IndexBuilder.ts b/plugins/search-backend-node/src/IndexBuilder.ts
index 768dee5b67..71d374e704 100644
--- a/plugins/search-backend-node/src/IndexBuilder.ts
+++ b/plugins/search-backend-node/src/IndexBuilder.ts
@@ -98,7 +98,7 @@ export class IndexBuilder {
   async build(): Promise<{ scheduler: Scheduler }> {
     const scheduler = new Scheduler({ logger: this.logger });
 
-    Object.keys(this.collators).map(type => {
+    Object.keys(this.collators).forEach(type => {
       scheduler.addToSchedule(async () => {
         // Collate, Decorate, Index.
         const decorators: DocumentDecorator[] = (

From 4906a4c2210c38e1364bf69c882ab90df2fc7f3c Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Tue, 27 Apr 2021 11:07:55 +0200
Subject: [PATCH 12/13] rename test file to be more specific to IndexBuilder

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 .../src/{index.test.ts => IndexBuilder.test.ts}                   | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename plugins/search-backend-node/src/{index.test.ts => IndexBuilder.test.ts} (100%)

diff --git a/plugins/search-backend-node/src/index.test.ts b/plugins/search-backend-node/src/IndexBuilder.test.ts
similarity index 100%
rename from plugins/search-backend-node/src/index.test.ts
rename to plugins/search-backend-node/src/IndexBuilder.test.ts

From 6c46febf6326a8a119529e2b37f2029178fa7a3e Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Tue, 27 Apr 2021 11:08:37 +0200
Subject: [PATCH 13/13] Add tests for Scheduler

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
---
 .../search-backend-node/src/Scheduler.test.ts | 77 +++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 plugins/search-backend-node/src/Scheduler.test.ts

diff --git a/plugins/search-backend-node/src/Scheduler.test.ts b/plugins/search-backend-node/src/Scheduler.test.ts
new file mode 100644
index 0000000000..43fdb7ea92
--- /dev/null
+++ b/plugins/search-backend-node/src/Scheduler.test.ts
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { getVoidLogger } from '@backstage/backend-common';
+import { Scheduler } from './index';
+
+describe('Scheduler', () => {
+  let testScheduler: Scheduler;
+
+  beforeEach(() => {
+    const logger = getVoidLogger();
+    testScheduler = new Scheduler({
+      logger,
+    });
+  });
+
+  describe('addToSchedule', () => {
+    it('should not add a task and interval to schedule, if already started', async () => {
+      jest.useFakeTimers();
+      const mockTask1 = jest.fn();
+      const mockTask2 = jest.fn();
+
+      // Add a task and interval to schedule
+      testScheduler.addToSchedule(mockTask1, 2);
+
+      // Starts scheduling process
+      testScheduler.start();
+
+      // Throws Error if task and interval is added to a already started schedule
+      expect(() => testScheduler.addToSchedule(mockTask2, 2)).toThrowError();
+
+      jest.runOnlyPendingTimers();
+      expect(mockTask1).toHaveBeenCalled();
+      expect(mockTask2).not.toHaveBeenCalled();
+    });
+
+    it('should be possible to add a task and interval to schedule, if already started, but stopped in between', async () => {
+      jest.useFakeTimers();
+      const mockTask1 = jest.fn();
+      const mockTask2 = jest.fn();
+
+      // Add a task and interval to schedule
+      testScheduler.addToSchedule(mockTask1, 2);
+
+      // Starts scheduling process
+      testScheduler.start();
+
+      // Stop scheduling process
+      testScheduler.stop();
+
+      // Should't throw error, as it is stopped.
+      expect(() =>
+        testScheduler.addToSchedule(mockTask2, 4),
+      ).not.toThrowError();
+
+      // Starts scheduling process
+      testScheduler.start();
+
+      jest.runOnlyPendingTimers();
+      expect(mockTask1).toHaveBeenCalled();
+      expect(mockTask2).toHaveBeenCalled();
+    });
+  });
+});