AU: Update Downloader to support our image formats.

src/platform/update_engine/utils_unittest.cc

Index: src/platform/update_engine/utils_unittest.cc
diff --git a/src/platform/update_engine/utils_unittest.cc b/src/platform/update_engine/utils_unittest.cc
index 74f349db1ebe4cc4689b604ed4903b0c6afad17a..5ab78cd228ea5a64cc54bc2caba0a835ea5bcc3a 100644
--- a/src/platform/update_engine/utils_unittest.cc
+++ b/src/platform/update_engine/utils_unittest.cc
@@ -88,6 +88,20 @@ TEST(UtilsTest, BootDeviceTest) {
   EXPECT_FALSE(utils::BootDevice().empty());
 }
 
+TEST(UtilsTest, BootKernelDeviceTest) {
+  EXPECT_EQ("", utils::BootKernelDevice("foo"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda0"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda1"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda2"));
+  EXPECT_EQ("/dev/sda2", utils::BootKernelDevice("/dev/sda3"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda4"));
+  EXPECT_EQ("/dev/sda4", utils::BootKernelDevice("/dev/sda5"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda6"));
+  EXPECT_EQ("/dev/sda6", utils::BootKernelDevice("/dev/sda7"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda8"));
+  EXPECT_EQ("", utils::BootKernelDevice("/dev/sda9"));
+}
+
 TEST(UtilsTest, RecursiveUnlinkDirTest) {
   EXPECT_EQ(0, mkdir("RecursiveUnlinkDirTest-a", 0755));
   EXPECT_EQ(0, mkdir("RecursiveUnlinkDirTest-b", 0755));