Add daily email for 2024-02-16

Keep logic within tests for as long as you can

source/_daily_emails/2024-02-16.md

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+---
+title: Keep logic within tests for as long as you can
+date: 2024-02-16
+permalink: archive/2024/02/16/keep-logic-within-tests-for-as-long-as-you-can
+snippet: |
+    Making the easy change to get a test to pass might mean you write more logic in your tests than you expect, at least to begin with.
+tags:
+    - software-development
+    - automated-testing
+    - test-driven-development
+    - drupal
+    - php
+    - phpunit
+---
+
+Inspired by some recent podcast guests, I've started writing the first code for a Drupal-based SaaS product that I've been thinking of creating.
+
+Here's an early iteration of the first test I wrote:
+
+```language-php
+public function test_it_creates_a_project_node_from_json(): void {
+  self::assertNull(Node::load(id: 1));
+
+  $this->installEntitySchema(entity_type_id: 'node');
+  $this->installConfig(modules: self::$modules);
+
+  $projectData = json_decode(json: self::$projectJson, associative: TRUE);
+  self::assertNotNull($projectData);
+
+  Node::create([
+    'title' => $projectData['list'][0]['title'],
+    'type' => 'drupal_project',
+  ])->save();
+
+  $node = Node::load(id: 1);
+
+  self::assertNotNull($node);
+  self::assertInstanceOf(actual: $node, expected: NodeInterface::class);
+  self::assertSame(actual: $node->label(), expected: 'Override Node Options');
+
+  self::assertSame(
+    actual: $node->get('field_drupalorg_node_id')->getString(),
+    expected: strval(107871),
+  );
+}
+```
+
+It checks that, given some defined JSON data, it will create a node in my database.
+
+It confirms no node ID exists when starting, runs some setup setups (this is a Kernel test), decodes the JSON, creates the node and asserts it contains the expected values.
+
+There are two things that you may be wondering...
+
+* Why do you have test setup code that you'll need within the test? Won't you need that for every test?
+* Why are you creating the node within the test and not somewhere else?
+
+The answer to both is that this is the first test, and I want to write **as little code as possible for it to pass**.
+
+When I write the second test, I'll either need to duplicate the setup lines or extract them to a `setUp()` method.
+
+I'll also need to refactor the code that creates the node.
+
+Once I've written the second test, to get it to pass, I refactored to use Repository, Builder and Action classes.
+
+If there's a regression, the test I had will fail, and I could revert to the passing version before reattempting the refactor.
+
+With test-driven development, I want to work in small and simple steps and get to green by making the smallest and easiest possible change.
+
+When I have a test that forces me to refactor and adopt a more complex approach, I'll do it.