chore(docs): update tutorial testing chapter

[shreyas44]

• Use the Prisma Client created in db.ts in the API Context
• Disconnect Prisma Client after running each test, allowing Jest to exit. Previously this was an issue as the Prisma Client connection was never closed and prevented Jest from exiting. This issue was fixed in a9ca189 using a workaround by passing the --forceExit flag to Jest.

This PR adds a proper fix for #678

[codecov]

Codecov Report

Merging #709 (54d3770) into develop (a9ca189) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #709      +/-   ##
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- Coverage    93.62%   93.62%   -0.01%     
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  Files           44       46       +2     
  Lines         2887     2900      +13     
  Branches       678      679       +1     
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+ Hits          2703     2715      +12     
- Misses         182      183       +1     
  Partials         2        2              

[jasonkuhrt]

Can you update this to match https://github.com/graphql-nexus/tutorial/blob/master/api/context.ts

I don't think we need a db modular just to instantiate a Prisma client :)

[shreyas44]

We don't need db to modular, but we do need to store the instance of the Prisma Client in either an object or variable which is exported so that it can be accessed in tests/__helpers.ts. The same Prisma Client used in the context of Nexus should be accessible in __helpers.ts as a new connection is created for every instance of Prisma Client.

There are two options, one is keep it as I've updated it.

Another is, to export an object from 'context.ts' and disconnect the connection of that

export const context: Context = {
  db: new PrismaClient()
}

and in __helpers.ts

import { context } from '../api/context.ts'

... 

function graphqlTestContext() {
  ...
  
  return {
    async before() {
      ...
      serverInstance.server.on('close', async () => {
        await context.db.$disconnect()
      })
    },
    ...
  }
}

[jasonkuhrt]

Yep good point. then a singleton db module is a simple solution indeed. If you're inclined update the tutorial repo otherwise we'll try to do it soon.

[shreyas44]

Already done graphql-nexus/tutorial#13 🙂 !

[jasonkuhrt]

Awesome! Just one thing