diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 61884ea95..4ba1fbeb9 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -22,6 +22,7 @@ jobs:
             - uses: shivammathur/setup-php@v2
               with:
                   php-version: ${{ matrix.php }}
+                  extensions: ds
                   coverage: none
 
             - run: composer install --no-progress --prefer-dist
@@ -41,6 +42,7 @@ jobs:
             - uses: shivammathur/setup-php@v2
               with:
                   php-version: 7.4
+                  extensions: ds
                   coverage: none
 
             - run: composer install --no-progress --prefer-dist
diff --git a/tests/Tracy/Dumper.toText().specials.ds.phpt b/tests/Tracy/Dumper.toText().specials.ds.phpt
new file mode 100644
index 000000000..bc1d64ede
--- /dev/null
+++ b/tests/Tracy/Dumper.toText().specials.ds.phpt
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Test: Tracy\Dumper::toText() specials
+ */
+
+declare(strict_types=1);
+
+use Tester\Assert;
+use Tracy\Dumper;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+// ext-ds collection
+$collection = new \Ds\Vector(['value']);
+Assert::match(<<<'XX'
+Ds\Vector #%d%
+   0: 'value'
+XX
+, Dumper::toText($collection));
+
+
+// ext-ds map
+$map = new \Ds\Map;
+$map->put('key', 'value');
+Assert::match(<<<'XX'
+Ds\Map #%d%
+   0: Ds\Pair #%d%
+   |  key: 'key'
+   |  value: 'value'
+XX
+, Dumper::toText($map));