Avoid undefined behavior in BPTCCompressedTextureTest

src/tests/gl_tests/BPTCCompressedTextureTest.cpp

@@ -21,7 +21,10 @@ const unsigned int kPixelTolerance = 1u;
 const std::array<GLubyte, 16> kBC7Data4x4 = {0x50, 0x1f, 0xfc, 0xf, 0x0,  0xf0, 0xe3, 0xe1,
                                              0xe1, 0xe1, 0xc1, 0xf, 0xfc, 0xc0, 0xf,  0xfc};
 
-const std::array<GLubyte, 16> kBC7BlackData4x4 = {};
+// The pixel data represents a 4x4 pixel image with the transparent black solid color.
+// Sampling from a zero-filled block is undefined, so use a valid one.
+const std::array<GLubyte, 16> kBC7BlackData4x4 = {0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                                                  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
 }  // anonymous namespace
 
 class BPTCCompressedTextureTest : public ANGLETest
@@ -273,9 +276,6 @@ TEST_P(BPTCCompressedTextureTestES3, CopyTexSubImage3DDisallowed)
 // Test uploading texture data from a PBO to a texture.
 TEST_P(BPTCCompressedTextureTestES3, PBOCompressedTexImage)
 {
-    // TODO(anglebug.com/5360): Failing on ARM-based Apple DTKs.
-    ANGLE_SKIP_TEST_IF(IsOSX() && IsARM64() && IsMetal());
-
     ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_texture_compression_bptc"));
 
     GLTexture texture;
@@ -327,9 +327,6 @@ TEST_P(BPTCCompressedTextureTestES3, PBOCompressedTexImage)
 // Test uploading texture data from a PBO to a non-zero base texture.
 TEST_P(BPTCCompressedTextureTestES3, PBOCompressedTexImageNonZeroBase)
 {
-    // TODO(anglebug.com/5360): Failing on ARM-based Apple DTKs.
-    ANGLE_SKIP_TEST_IF(IsOSX() && IsARM64() && IsMetal());
-
     ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_texture_compression_bptc"));
 
     GLTexture texture;