vulkan: Add a regression (unit) test

Add a small test that verifies that the Vulkan version can
be found given the VULKAN_SDK path.

Author: amolenaar

unittests/vulkantests.py

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2016-2025 The Meson development team
+
+import tempfile
+import textwrap
+from pathlib import Path
+from unittest import mock
+
+from .baseplatformtests import BasePlatformTests
+from mesonbuild.compilers.mixins.clike import CLikeCompiler
+
+
+class VulkanTests(BasePlatformTests):
+
+    def test_vulkan_sdk_environment_variable(self):
+        '''
+        Test that the SDK version pointed to by the VULKAN_SDK
+        environment variable is found.
+        In this test we're only interested in finding the Vulkan
+        version. Finding the library is mocked.
+        '''
+        with tempfile.TemporaryDirectory() as tmpdir:
+            sdk_path = Path(tmpdir) / 'VulkanSDK'
+            include_path = sdk_path / 'include' / 'vulkan'
+            include_path.mkdir(parents=True)
+            (include_path / 'vulkan.h').write_text(textwrap.dedent(
+                '''\
+                #define VK_HEADER_VERSION_COMPLETE "dummy"
+
+                #define VK_VERSION_MAJOR(version) (1)
+                #define VK_VERSION_MINOR(version) (3)
+                #define VK_VERSION_PATCH(version) (123456789)
+                '''),
+                encoding='utf-8'
+            )
+
+            project_path = Path(tmpdir) / 'project'
+            project_path.mkdir()
+            (project_path / 'meson.build').write_text(textwrap.dedent(
+                '''\
+                project('vulkan test', 'c')
+                vulkan_dep = dependency('vulkan', required : true)
+                message('Found Vulkan version:', vulkan_dep.version())
+                '''),
+                encoding='utf-8'
+            )
+
+            with mock.patch.object(CLikeCompiler, 'find_library', return_value=['dummy-lib']):
+                out = self.init(str(project_path), override_envvars={'VULKAN_SDK': str(sdk_path)}, inprocess=True)
+
+        self.assertIn('Found Vulkan version: 1.3.123456789', out)