Feat: Improve context builder (#48)

src/Internal/EtlBuilderTrait.php

@@ -18,6 +18,7 @@
 use BenTools\ETL\Transformer\ChainTransformer;
 use BenTools\ETL\Transformer\TransformerInterface;
 
+use function array_intersect_key;
 use function count;
 
 /**
@@ -112,8 +113,12 @@ public function withProcessor(ProcessorInterface $processor): self
     /**
      * @param array<string, mixed> $context
      */
-    public function withContext(array $context): self
+    public function withContext(array $context, bool $clear = false, bool $overwrite = true): self
     {
-        return $this->cloneWith(['context' => $context]);
+        return $this->cloneWith(['context' => [
+            ...($clear ? [] : $this->context),
+            ...$context,
+            ...($overwrite ? [] : array_intersect_key($this->context, $context)),
+        ]]);
     }
 }

tests/Unit/ContextTest.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace BenTools\ETL\Tests\Unit;
+
+use BenTools\ETL\EtlExecutor;
+
+use function expect;
+use function it;
+
+it('provides a default context', function () {
+    // Given
+    $executor = (new EtlExecutor(context: ['color' => 'green', 'shape' => 'square', 'lights' => 'on']));
+
+    // When
+    $report = $executor->process([], context: ['shape' => 'round', 'size' => 'small']);
+
+    // Then
+    expect($report->context)->toBe(['color' => 'green', 'shape' => 'round', 'lights' => 'on', 'size' => 'small']);
+});
+
+it('adds some more context', function () {
+    // Given
+    $executor = (new EtlExecutor(context: ['color' => 'green', 'shape' => 'square', 'lights' => 'on']))
+        ->withContext(['color' => 'blue', 'flavor' => 'vanilla']);
+
+    // When
+    $report = $executor->process([], context: ['shape' => 'round', 'size' => 'small']);
+
+    // Then
+    expect($report->context)->toBe(['color' => 'blue', 'shape' => 'round', 'lights' => 'on', 'flavor' => 'vanilla', 'size' => 'small']);
+});
+
+it('replaces the whole context', function () {
+    // Given
+    $executor = (new EtlExecutor(context: ['color' => 'green', 'shape' => 'square', 'lights' => 'on']))
+        ->withContext(['color' => 'blue', 'flavor' => 'vanilla'], clear: true);
+
+    // When
+    $report = $executor->process([], context: ['shape' => 'round', 'size' => 'small']);
+
+    // Then
+    expect($report->context)->toBe(['color' => 'blue', 'flavor' => 'vanilla', 'shape' => 'round', 'size' => 'small']);
+});
+
+it('does not override existing values', function () {
+    // Given
+    $executor = (new EtlExecutor(context: ['color' => 'green', 'shape' => 'square', 'lights' => 'on']))
+        ->withContext(['color' => 'blue', 'flavor' => 'vanilla'], overwrite: false);
+
+    // When
+    $report = $executor->process([], context: ['shape' => 'round', 'size' => 'small']);
+
+    // Then
+    expect($report->context)->toBe(['color' => 'green', 'shape' => 'round', 'lights' => 'on', 'flavor' => 'vanilla', 'size' => 'small']);
+});

tests/Unit/EtlExecutorTest.php

@@ -114,14 +114,3 @@ public function process(EtlExecutor $executor, EtlState $state, mixed $extracted
     // When
     $executor->process([]);
 })->throws(ExtractException::class);
-
-it('accepts a default context', function () {
-    // Given
-    $executor = (new EtlExecutor())->withContext(['foo' => 'bar']);
-
-    // When
-    $report = $executor->process([], context: ['bar' => 'baz']);
-
-    // Then
-    expect($report->context)->toBe(['foo' => 'bar', 'bar' => 'baz']);
-});