02/02: add exercise

Author: kettanaito

exercises/02.test-setup/02.problem.mock-databases/README.mdx

@@ -0,0 +1,11 @@
+# Mock databases
+
+Problem: Your app under test **must not** communicate with the actual database.
+
+Mocking database connections is database-specific. There are serveral kinds of databases you might be using:
+
+- **File-based** (SQLite). Just point it to a local file;
+- **Server-based** (Postgres). You can run that DB instance locally in a Docker image and point your DB client to that locally running DB instance.
+- **In-memory databases** (Redis). Run database locally (that's usually easier and doesn't require Docker), connect to the locally running instance.
+
+> Some database clients, like Supabase, might also expose an additional layer between your application and the database. You might decide to tap into that, too.

exercises/02.test-setup/02.problem.mock-databases/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "exercises_02.test-setup_02.problem.mock-databases"
+}

exercises/02.test-setup/02.solution.mock-databases/README.mdx

@@ -1,9 +1,10 @@
 # Mock databases
 
-**This exercise MUST preceed the Authentication exercise** because we are using Prisma to create test users for authentication purposes. Without this setup, it will try creating real users in the real database.
+Good job! 👏
 
-- **Set up mock databases _per test_.** `testInfo.testId` to the rescue! But then it's not environment variable-driven so be cautious.
+Take a quick rest and let's continue.
 
-1. Create `.env.test` and load it in Playwright.
-1. Set `DATABASE_URL` environment variable to point to `./prisma.data.db`.
-1. Show how that datbase after the test run (see the created user).
+## Related materials
+
+- [PostgreSQL test setup with Prisma](https://www.prisma.io/docs/orm/prisma-client/testing/integration-testing)
+- [Redus test setup (Node.js)](https://redis.io/docs/latest/develop/clients/nodejs/)

exercises/02.test-setup/04.solution.api-mocking/prisma/data-new.db

@@ -22,6 +22,9 @@
     {
       "path": "exercises/02.test-setup/01.solution.custom-fixtures"
     },
+    {
+      "path": "exercises/02.test-setup/02.problem.mock-databases"
+    },
     {
       "path": "exercises/02.test-setup/02.solution.mock-databases"
     },