fix(java-yoshi): throw MissingRequiredFile error if no versions.txt found (#1794)

* test: failing test for missing required file

* fix: java-yoshi strategy should throw MissingRequiredFile error if no versions.txt found

Author: chingor13

src/strategies/java-yoshi.ts

@@ -17,7 +17,7 @@ import {VersionsManifest} from '../updaters/java/versions-manifest';
 import {Version, VersionsMap} from '../version';
 import {Changelog} from '../updaters/changelog';
 import {GitHubFileContents} from '@google-automations/git-file-utils';
-import {GitHubAPIError, MissingRequiredFileError} from '../errors';
+import {MissingRequiredFileError, FileNotFoundError} from '../errors';
 import {ConventionalCommit} from '../commit';
 import {Java, JavaBuildUpdatesOption} from './java';
 import {JavaUpdate} from '../updaters/java/java-update';
@@ -70,7 +70,7 @@ export class JavaYoshi extends Java {
           this.targetBranch
         );
       } catch (err) {
-        if (err instanceof GitHubAPIError) {
+        if (err instanceof FileNotFoundError) {
           throw new MissingRequiredFileError(
             this.addPath('versions.txt'),
             JavaYoshi.name,

test/strategies/java-yoshi.ts

@@ -29,6 +29,7 @@ import {Changelog} from '../../src/updaters/changelog';
 import {JavaUpdate} from '../../src/updaters/java/java-update';
 import {VersionsManifest} from '../../src/updaters/java/versions-manifest';
 import {CompositeUpdater} from '../../src/updaters/composite';
+import {FileNotFoundError, MissingRequiredFileError} from '../../src/errors';
 
 const sandbox = sinon.createSandbox();
 const fixturesPath = './test/fixtures/strategies/java-yoshi';
@@ -180,6 +181,34 @@ describe('JavaYoshi', () => {
         versionsMap.get('grpc-google-cloud-trace-v1beta1')?.toString()
       ).to.eql('0.74.0');
     });
+    it('throws on missing required versions.txt', async () => {
+      const strategy = new JavaYoshi({
+        targetBranch: 'main',
+        github,
+        component: 'google-cloud-automl',
+      });
+      sandbox.stub(github, 'findFilesByFilenameAndRef').resolves([]);
+      const getFileContentsStub = sandbox.stub(
+        github,
+        'getFileContentsOnBranch'
+      );
+      getFileContentsStub
+        .withArgs('versions.txt', 'main')
+        .throws(new FileNotFoundError('versions.txt'));
+      const latestRelease = {
+        tag: new TagName(Version.parse('0.123.4'), 'google-cloud-automl'),
+        sha: 'abc123',
+        notes: 'some notes',
+      };
+      let failed = false;
+      try {
+        await strategy.buildReleasePullRequest(COMMITS, latestRelease);
+      } catch (e) {
+        expect(e).instanceof(MissingRequiredFileError);
+        failed = true;
+      }
+      expect(failed).to.be.true;
+    });
   });
   describe('buildUpdates', () => {
     it('builds common files', async () => {