fix: stabilize apps:diff 404 tests by mocking both apps (#3585)

Author: michaelmalave

test/unit/commands/apps/diff.unit.test.ts

@@ -132,6 +132,8 @@ describe('apps:diff', function () {
   it('throws App not found when one app returns 404 on releases', async function () {
     api
       .get(`/apps/${app1Name}/releases`).matchHeader('range', /version/).reply(404, {id: 'not_found', message: 'Couldn\'t find that app.'})
+      .get(`/apps/${app2Name}/releases`).matchHeader('range', /version/).reply(200, releasesWithSlug(slugId2))
+      .get(`/apps/${app2Name}/slugs/${slugId2}`).reply(200, slugBody(sameChecksum))
 
     const {error} = await runCommand(AppsDiff, [app1Name, app2Name])
 
@@ -144,6 +146,8 @@ describe('apps:diff', function () {
     api
       .get(`/apps/${app1Name}/releases`).matchHeader('range', /version/).reply(200, releasesWithSlug(slugId1))
       .get(`/apps/${app1Name}/slugs/${slugId1}`).reply(404, {id: 'not_found', message: 'Not found'})
+      .get(`/apps/${app2Name}/releases`).matchHeader('range', /version/).reply(200, releasesWithSlug(slugId2))
+      .get(`/apps/${app2Name}/slugs/${slugId2}`).reply(200, slugBody(sameChecksum))
 
     const {error} = await runCommand(AppsDiff, [app1Name, app2Name])