PHPLIB-1355 Add tests to $meta expression

generator/config/expression/meta.yaml

@@ -11,3 +11,29 @@ arguments:
         name: keyword
         type:
             - string
+tests:
+    -
+        name: 'textScore'
+        link: 'https://www.mongodb.com/docs/manual/reference/operator/aggregation/meta/#-meta---textscore-'
+        pipeline:
+            -
+                $match:
+                    $text:
+                        $search: 'cake'
+            -
+                $group:
+                    _id:
+                        $meta: 'textScore'
+                    count:
+                        $sum: 1
+    -
+        name: 'indexKey'
+        link: 'https://www.mongodb.com/docs/manual/reference/operator/aggregation/meta/#-meta---indexkey-'
+        pipeline:
+            -
+                $match:
+                    type: 'apparel'
+            -
+                $addFields:
+                    idxKey:
+                        $meta: 'indexKey'

tests/Builder/Expression/MetaOperatorTest.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MongoDB\Tests\Builder\Expression;
+
+use MongoDB\Builder\Accumulator;
+use MongoDB\Builder\Expression;
+use MongoDB\Builder\Pipeline;
+use MongoDB\Builder\Query;
+use MongoDB\Builder\Stage;
+use MongoDB\Tests\Builder\PipelineTestCase;
+
+/**
+ * Test $meta expression
+ */
+class MetaOperatorTest extends PipelineTestCase
+{
+    public function testIndexKey(): void
+    {
+        $pipeline = new Pipeline(
+            Stage::match(
+                type: 'apparel',
+            ),
+            Stage::addFields(
+                idxKey: Expression::meta('indexKey'),
+            ),
+        );
+
+        $this->assertSamePipeline(Pipelines::MetaIndexKey, $pipeline);
+    }
+
+    public function testTextScore(): void
+    {
+        $pipeline = new Pipeline(
+            Stage::match(
+                Query::text(
+                    search: 'cake',
+                ),
+            ),
+            Stage::group(
+                _id: Expression::meta('textScore'),
+                count: Accumulator::sum(1),
+            ),
+        );
+
+        $this->assertSamePipeline(Pipelines::MetaTextScore, $pipeline);
+    }
+}