ANGLE: Add validation test for GL_RENDERER string format

This change introduces a new ANGLE end-to-end test to validate the
format of the GL_RENDERER string, preventing regressions caused by
downstream modifications.

A recent issue (b/318636997) was caused by a partner modifying the
ANGLE GL_RENDERER string in a way that broke Skia's parser. This
revealed that the string format is a de-facto API contract that must
be enforced.

This new test, RendererTest.ValidateCanonicalFormat, serves as an
automated guardrail and will become part of the Android CTS.

The test enforces the following structural contract:
1.  The overall structure must be "ANGLE (Vendor, Renderer, Version)".
2.  The separator between components must be ", ".
3.  The Vendor, Renderer, and Version components must not be empty.

This ensures the string is parsable by clients like Skia without
over-constraining the content of the component strings, which may
originate from underlying drivers.

The test correctly skips validation on the Null backend, which is not
subject to this contract.

Test: autoninja -C out/Android angle_end2end_tests && out/Android/angle_end2end_tests --gtest_filter="RendererTest.*" --num-retries=0
Bug: b/432805963
Change-Id: I1202074cc9f4413ee88e4534fb72fb71101721e3
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6788522
Reviewed-by: Cody Northrop <[email protected]>
Commit-Queue: Solti Ho <[email protected]>
Reviewed-by: Shahbaz Youssefi <[email protected]>

Author: SoltiGG

src/tests/gl_tests/RendererTest.cpp

@@ -9,6 +9,7 @@
 //   configured incorrectly. For example, they might be using the D3D11 renderer when the test is
 //   meant to be using the D3D9 renderer.
 
+#include <regex>
 #include "common/string_utils.h"
 #include "test_utils/ANGLETest.h"
 #include "test_utils/gl_raii.h"
@@ -212,10 +213,51 @@ TEST_P(RendererTest, Draw)
     glDrawArrays(GL_TRIANGLES, 0, 3);
 }
 
+// This test validates that the GL_RENDERER string reported by ANGLE adheres to the
+// canonical format: "ANGLE (Vendor, Renderer, Version)".
+// This format is a de-facto API contract relied upon by upstream clients like Skia
+// to enable workarounds and optimizations.
+TEST_P(RendererTest, ValidateCanonicalFormat)
+{
+    // Use the idiomatic IsNULL() check to skip this test on the Null backend.
+    if (IsNULL())
+    {
+        std::cout << "Skipping canonical format validation for the Null backend." << std::endl;
+        return;
+    }
+
+    // 1. Query the renderer string from the driver.
+    const char *rendererCStr = reinterpret_cast<const char *>(glGetString(GL_RENDERER));
+    ASSERT_NE(rendererCStr, nullptr);
+    std::string rendererStr(rendererCStr);
+    std::cout << "Renderer string: \"" << rendererStr << "\"" << std::endl;
+
+    // 2. Validate the entire string structure using a single regular expression.
+    //    This regex enforces the "ANGLE (...)" wrapper and the presence of three
+    //    comma-space-separated components, while allowing components to be empty.
+    const std::regex kRendererFormat("^ANGLE \\((.*), (.*), (.*)\\)$");
+    std::smatch match;
+
+    bool matches = std::regex_match(rendererStr, match, kRendererFormat);
+
+    // 3. Assert that the string matches the format and contains the correct number of groups.
+    //    match[0] is the full string, match[1-3] are the captured components.
+    ASSERT_TRUE(matches && match.size() == 4)
+        << "Renderer string does not match the expected format 'ANGLE (Vendor, Renderer, Version)'."
+        << "\n  Actual string: " << rendererStr;
+
+    // 4. For clarity in test logs, print the parsed components.
+    std::cout << "Successfully parsed renderer string components:" << std::endl;
+    std::cout << "  - Vendor:   \"" << match[1].str() << "\"" << std::endl;
+    std::cout << "  - Renderer: \"" << match[2].str() << "\"" << std::endl;
+    std::cout << "  - Version:  \"" << match[3].str() << "\"" << std::endl;
+
+    EXPECT_GL_NO_ERROR();
+}
+
 // Select configurations (e.g. which renderer, which GLES major version) these tests should be run
 // against.
 // TODO(http://anglebug.com/42266907): move ES2_WEBGPU to the definition of
 // ANGLE_ALL_TEST_PLATFORMS_ES2 once webgpu is developed enough to run more tests.
-ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND_ES31_AND_NULL_AND(RendererTest,
-                                                         ES2_WEBGPU());
+ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND_ES31_AND_NULL_AND(RendererTest, ES2_WEBGPU());
 }  // namespace angle