Add tests for specialize_cell_shader() to kitty_tests/shaders.py

kitty_tests/shaders.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2026, Kovid Goyal <kovid at kovidgoyal.net>
+
+import os
+import tempfile
+from unittest.mock import patch
+
+from kitty.options.types import defaults
+from kitty.shaders.slang import specialize_cache, specialize_cell_shader
+
+from . import BaseTest
+
+
+class TestShaders(BaseTest):
+
+    def test_specialize_cell_shader(self):
+        specialize_cache.clear()
+
+        # No action when opts are the same as defaults
+        self.assertEqual(specialize_cell_shader(opts=defaults), {})
+
+        # Mock out compilation to avoid needing slangc
+        call_count = [0]
+
+        def fake_specialize_shaders_to(sources, dest_dir):
+            call_count[0] += 1
+            with open(os.path.join(dest_dir, 'cell.glsl'), 'wb') as f:
+                f.write(b'fake shader ' + str(call_count[0]).encode())
+
+        def fake_ensure_cache_dir(path):
+            os.makedirs(path, exist_ok=True)
+
+        with patch('kitty.shaders.slang.specialize_shaders_to', fake_specialize_shaders_to), \
+             patch('kitty.shaders.slang.ensure_cache_dir', fake_ensure_cache_dir):
+
+            # Changing options produces non-empty shaders
+            opts1 = defaults._replace(text_composition_strategy='legacy')
+            with tempfile.TemporaryDirectory() as dir1:
+                result1 = specialize_cell_shader(create_cache_dir=lambda: dir1, opts=opts1)
+            self.assertNotEqual(result1, {})
+
+            # Changing to different options produces different shaders
+            opts2 = defaults._replace(text_fg_override_threshold=(10.0, '%'))
+            with tempfile.TemporaryDirectory() as dir2:
+                result2 = specialize_cell_shader(create_cache_dir=lambda: dir2, opts=opts2)
+            self.assertNotEqual(result2, {})
+            self.assertNotEqual(result1, result2)
+
+            # Calling twice with the same options returns the same object
+            opts3 = defaults._replace(text_composition_strategy='legacy')
+            with tempfile.TemporaryDirectory() as dir3:
+                get_dir3 = lambda: dir3
+                result3a = specialize_cell_shader(create_cache_dir=get_dir3, opts=opts3)
+                result3b = specialize_cell_shader(create_cache_dir=get_dir3, opts=opts3)
+            self.assertIs(result3a, result3b)