Add tests for fetchTechDocsMetadata

Signed-off-by: vitorgrenzel <vitorgrenzel@gmail.com>

packages/techdocs-common/__mocks__/@azure/storage-blob.ts

@@ -17,6 +17,7 @@ import type {
   BlobUploadCommonResponse,
   ContainerGetPropertiesResponse,
 } from '@azure/storage-blob';
+import { EventEmitter } from 'events';
 import fs from 'fs-extra';
 import os from 'os';
 import path from 'path';
@@ -62,6 +63,24 @@ export class BlockBlobClient {
   exists() {
     return checkFileExists(this.blobName);
   }
+
+  download() {
+    const emitter = new EventEmitter();
+    process.nextTick(() => {
+      if (fs.existsSync(this.blobName)) {
+        emitter.emit('data', Buffer.from(fs.readFileSync(this.blobName)));
+      } else {
+        emitter.emit(
+          'error',
+          new Error(`The file ${this.blobName} doest not exist!`),
+        );
+      }
+      emitter.emit('end');
+    });
+    return Promise.resolve({
+      readableStreamBody: emitter,
+    });
+  }
 }
 
 class BlockBlobClientFailUpload extends BlockBlobClient {

packages/techdocs-common/src/stages/publish/azureBlobStorage.test.ts

@@ -20,8 +20,9 @@ import mockFs from 'mock-fs';
 import os from 'os';
 import path from 'path';
 import { AzureBlobStoragePublish } from './azureBlobStorage';
-import { PublisherBase } from './types';
-
+import { PublisherBase, TechDocsMetadata } from './types';
+import type { Entity, EntityName } from '@backstage/catalog-model';
+import type { Logger } from 'winston';
 // NOTE: /packages/techdocs-common/__mocks__ is being used to mock Azure client library
 
 const createMockEntity = (annotations = {}) => {
@@ -38,6 +39,12 @@ const createMockEntity = (annotations = {}) => {
   };
 };
 
+const createMockEntityName = (): EntityName => ({
+  kind: 'TestKind',
+  name: 'test-component-name',
+  namespace: 'test-namespace',
+});
+
 const rootDir = os.platform() === 'win32' ? 'C:\\rootDir' : '/rootDir';
 const getEntityRootDir = (entity: Entity) => {
   const {
@@ -255,4 +262,60 @@ describe('error reporting', () => {
 
     mockFs.restore();
   });
+
+  describe('fetchTechDocsMetadata', () => {
+    it('should return tech docs metadata', async () => {
+      const entityNameMock = createMockEntityName();
+      const entity = createMockEntity();
+      const entityRootDir = getEntityRootDir(entity);
+
+      mockFs({
+        [entityRootDir]: {
+          'techdocs_metadata.json':
+            '{"site_name": "backstage", "site_description": "site_content"}',
+        },
+      });
+      const expectedMetadata: TechDocsMetadata = {
+        site_name: 'backstage',
+        site_description: 'site_content',
+      };
+      expect(
+        await publisher.fetchTechDocsMetadata(entityNameMock),
+      ).toStrictEqual(expectedMetadata);
+      mockFs.restore();
+    });
+
+    it('should return tech docs metadata when json encoded with single quotes', async () => {
+      const entityNameMock = createMockEntityName();
+      const entity = createMockEntity();
+      const entityRootDir = getEntityRootDir(entity);
+
+      mockFs({
+        [entityRootDir]: {
+          'techdocs_metadata.json': `{'site_name': 'backstage', 'site_description': 'site_content'}`,
+        },
+      });
+
+      const expectedMetadata: TechDocsMetadata = {
+        site_name: 'backstage',
+        site_description: 'site_content',
+      };
+      expect(
+        await publisher.fetchTechDocsMetadata(entityNameMock),
+      ).toStrictEqual(expectedMetadata);
+      mockFs.restore();
+    });
+
+    it('should return an error if the techdocs_metadata.json file is not present', async () => {
+      const entityNameMock = createMockEntityName();
+
+      await publisher
+        .fetchTechDocsMetadata(entityNameMock)
+        .catch(error =>
+          expect(error.message).toEqual(
+            expect.stringContaining('TechDocs metadata fetch'),
+          ),
+        );
+    });
+  });
 });

packages/techdocs-common/src/stages/publish/azureBlobStorage.ts

@@ -201,13 +201,13 @@ export class AzureBlobStoragePublish implements PublisherBase {
             return;
           }
           body
+            .on('data', chunk => {
+              fileStreamChunks.push(chunk);
+            })
             .on('error', e => {
               this.logger.error(e.message);
               reject(e.message);
             })
-            .on('data', chunk => {
-              fileStreamChunks.push(chunk);
-            })
             .on('end', () => {
               resolve(Buffer.concat(fileStreamChunks));
             });
@@ -220,16 +220,28 @@ export class AzureBlobStoragePublish implements PublisherBase {
   ): Promise<TechDocsMetadata> {
     const entityRootDir = `${entityName.namespace}/${entityName.kind}/${entityName.name}`;
     try {
-      return await new Promise<TechDocsMetadata>(resolve => {
-        const download = this.download(
-          this.containerName,
-          `${entityRootDir}/techdocs_metadata.json`,
-        );
-        resolve(JSON5.parse(download.toString()));
+      return await new Promise<TechDocsMetadata>(async (resolve, reject) => {
+        try {
+          const techdocsMetadataJson = await this.download(
+            this.containerName,
+            `${entityRootDir}/techdocs_metadata.json`,
+          );
+          if (!techdocsMetadataJson) {
+            throw new Error(
+              `Unable to parse the techdocs metadata file ${entityRootDir}/techdocs_metadata.json.`,
+            );
+          }
+          const techdocsMetadata = JSON5.parse(
+            techdocsMetadataJson.toString('utf-8'),
+          );
+          resolve(techdocsMetadata);
+        } catch (err) {
+          this.logger.error(err.message);
+          reject(new Error(err.message));
+        }
       });
     } catch (e) {
-      this.logger.error(e.message);
-      throw e;
+      throw new Error(`TechDocs metadata fetch failed, ${e.message}`);
     }
   }