diff --git a/docker-bake.hcl b/docker-bake.hcl
index a5600dc0..a345b98a 100644
--- a/docker-bake.hcl
+++ b/docker-bake.hcl
@@ -112,6 +112,8 @@ target "php-test" {
   context = "php"
   target = "tested"
   contexts = {
+    # replaces the stage that does `git clone` and ensures we get a fresh version
+    cck = "https://github.com/cucumber/compatibility-kit.git#main:devkit",
     schema-codegen = "target:php-codegen",
   }
 }
diff --git a/php/Dockerfile b/php/Dockerfile
index d3ceee5d..67af39bb 100644
--- a/php/Dockerfile
+++ b/php/Dockerfile
@@ -9,6 +9,15 @@ WORKDIR /cucumber
 FROM scratch AS schema-codegen
 
 
+# Stage to download the CCK data, overridden in main build but included here in case building in the subfolder
+# NB - when buildkit 1.5 is released this can be replaced with an ADD from the git URL
+FROM bitnami/git AS cck
+RUN git clone https://github.com/cucumber/compatibility-kit.git \
+    && cd compatibility-kit \
+    && git checkout main \
+    && cp -R ./devkit/samples /samples
+
+
 FROM php AS with-dependencies
 
 COPY --link composer.json .
@@ -23,6 +32,7 @@ FROM php AS tested
 COPY --link . .
 COPY --link --from=with-dependencies /cucumber/vendor vendor
 COPY --link --from=schema-codegen / src-generated
+COPY --link --from=cck /samples/ ./tests/cck-samples
 RUN vendor/bin/php-cs-fixer --dry-run --diff fix
 RUN vendor/bin/psalm --no-cache
 RUN vendor/bin/phpunit
diff --git a/php/composer.json b/php/composer.json
index 8349570d..cda2780f 100644
--- a/php/composer.json
+++ b/php/composer.json
@@ -28,7 +28,8 @@
             "Cucumber\\Messages\\": [
                 "src",
                 "src-generated",
-                "tests"
+                "tests",
+                "tests/unit"
             ]
         }
     }
diff --git a/php/phpunit.xml b/php/phpunit.xml
index fd5e5582..ea739e52 100644
--- a/php/phpunit.xml
+++ b/php/phpunit.xml
@@ -12,8 +12,11 @@
          failOnWarning="true"
          verbose="true">
     <testsuites>
-        <testsuite name="default">
-            <directory>tests</directory>
+        <testsuite name="unit">
+            <directory>tests/unit</directory>
+        </testsuite>
+        <testsuite name="end-to-end">
+            <file>tests/CckTest.php</file>
         </testsuite>
     </testsuites>
 
diff --git a/php/tests/AcceptanceTest.php b/php/tests/CckTest.php
similarity index 84%
rename from php/tests/AcceptanceTest.php
rename to php/tests/CckTest.php
index a3ce4ca4..151af1c7 100644
--- a/php/tests/AcceptanceTest.php
+++ b/php/tests/CckTest.php
@@ -1,11 +1,14 @@
 <?php
 
-use Cucumber\Messages\Envelope;
+namespace Cucumber\Messages;
+
 use Cucumber\Messages\Streams\NdJson\NdJsonStreamReader;
 use Cucumber\Messages\Streams\NdJson\NdJsonStreamWriter;
+use Exception;
+use Generator;
 use PHPUnit\Framework\TestCase;
 
-class AcceptanceTest extends TestCase
+class CckTest extends TestCase
 {
     /** @dataProvider provideJsonLines */
     public function testAllNdJsonSurvivesDecodingThenEncoding(string $json): void
@@ -74,6 +77,13 @@ public function provideNdJsonFilenames(): Generator
      */
     private function getSampleFiles(): array
     {
-        return glob(__DIR__ . '/../../../node_modules/@cucumber/compatibility-kit/features/**/*.ndjson') ?: [];
+        $files = glob(pattern:__DIR__ . '/cck-samples/**/*.ndjson');
+
+        // glob doesn't error if dir is empty
+        if ($files === []) {
+            throw new Exception('CCK sample files not found. Perhaps you want to run the "unit" testsuite?');
+        }
+
+        return $files;
     }
 }
diff --git a/php/tests/cck-samples/.gitignore b/php/tests/cck-samples/.gitignore
new file mode 100644
index 00000000..72e8ffc0
--- /dev/null
+++ b/php/tests/cck-samples/.gitignore
@@ -0,0 +1 @@
+*
diff --git a/php/tests/EnvelopeTest.php b/php/tests/unit/EnvelopeTest.php
similarity index 84%
rename from php/tests/EnvelopeTest.php
rename to php/tests/unit/EnvelopeTest.php
index a47922e6..77461530 100644
--- a/php/tests/EnvelopeTest.php
+++ b/php/tests/unit/EnvelopeTest.php
@@ -1,9 +1,7 @@
 <?php
 
-use Cucumber\Messages\Envelope;
-use Cucumber\Messages\Feature;
-use Cucumber\Messages\GherkinDocument;
-use Cucumber\Messages\Location;
+namespace Cucumber\Messages;
+
 use PHPUnit\Framework\TestCase;
 
 class EnvelopeTest extends TestCase
diff --git a/php/tests/Id/IdGeneratorTestTrait.php b/php/tests/unit/Id/IdGeneratorTestTrait.php
similarity index 100%
rename from php/tests/Id/IdGeneratorTestTrait.php
rename to php/tests/unit/Id/IdGeneratorTestTrait.php
diff --git a/php/tests/Id/IncrementingIdGeneratorTest.php b/php/tests/unit/Id/IncrementingIdGeneratorTest.php
similarity index 100%
rename from php/tests/Id/IncrementingIdGeneratorTest.php
rename to php/tests/unit/Id/IncrementingIdGeneratorTest.php
diff --git a/php/tests/Id/UuidIdGeneratorTest.php b/php/tests/unit/Id/UuidIdGeneratorTest.php
similarity index 100%
rename from php/tests/Id/UuidIdGeneratorTest.php
rename to php/tests/unit/Id/UuidIdGeneratorTest.php
diff --git a/php/tests/JsonDecodingTraitTest.php b/php/tests/unit/JsonDecodingTraitTest.php
similarity index 95%
rename from php/tests/JsonDecodingTraitTest.php
rename to php/tests/unit/JsonDecodingTraitTest.php
index 0383ff70..2505f6e6 100644
--- a/php/tests/JsonDecodingTraitTest.php
+++ b/php/tests/unit/JsonDecodingTraitTest.php
@@ -1,10 +1,13 @@
 <?php
 
+namespace Cucumber\Messages;
+
 use Cucumber\Messages\DecodingException\MalformedJsonException;
-use Cucumber\Messages\JsonEncodingTrait;
 use Cucumber\Messages\DecodingException\SchemaViolationException;
 use Cucumber\Messages\DecodingException\UnexpectedDecodingException;
+use JsonSerializable;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 
 class JsonDecodingTraitTest extends TestCase
 {