Move code for log archive to new helper class

This wil allow a test (like AuthFsHostTest) to stop sub-classing
VirtualizationTestCaseBase later.

Still keeps a wrapper method in the base class until the others are
migrated.

Bug: 218751146
Test: atest AuthFsHostTest ComposHostTestCases MicrodroidTestCase
Change-Id: If372b37b0f8cf23d66dfea8706b5cc92ba6f59f7
diff --git a/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java b/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java
index 0e660f1..52dbf7c 100644
--- a/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java
+++ b/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java
@@ -16,6 +16,8 @@
 
 package com.android.virt.fs;
 
+import static android.virt.test.LogArchiver.archiveLogThenDelete;
+
 import static com.android.tradefed.device.TestDevice.MicrodroidBuilder;
 import static com.android.tradefed.testtype.DeviceJUnit4ClassRunner.TestLogData;
 
diff --git a/tests/hostside/helper/java/android/virt/test/LogArchiver.java b/tests/hostside/helper/java/android/virt/test/LogArchiver.java
new file mode 100644
index 0000000..b6cae95
--- /dev/null
+++ b/tests/hostside/helper/java/android/virt/test/LogArchiver.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.virt.test;
+
+import static com.android.tradefed.testtype.DeviceJUnit4ClassRunner.TestLogData;
+
+import com.android.tradefed.device.DeviceNotAvailableException;
+import com.android.tradefed.device.ITestDevice;
+import com.android.tradefed.result.FileInputStreamSource;
+import com.android.tradefed.result.LogDataType;
+
+import java.io.File;
+
+/** A helper class for archiving device log files to the host's tradefed output directory. */
+public abstract class LogArchiver {
+    /** Copy device log (then delete) to a tradefed output directory on the host.
+     *
+     * @param logs A {@link TestLogData} that needs to be owned by the actual test case.
+     * @param device The device to pull the log file from.
+     * @param remotePath The path on the device.
+     * @param localName Local file name to be copied to.
+     */
+    public static void archiveLogThenDelete(TestLogData logs, ITestDevice device, String remotePath,
+            String localName) throws DeviceNotAvailableException {
+        File logFile = device.pullFile(remotePath);
+        if (logFile != null) {
+            logs.addTestLog(localName, LogDataType.TEXT, new FileInputStreamSource(logFile));
+            // Delete to avoid confusing logs from a previous run, just in case.
+            device.deleteFile(remotePath);
+        }
+    }
+}
diff --git a/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java b/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java
index 440ae18..dc0284f 100644
--- a/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java
+++ b/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java
@@ -30,8 +30,6 @@
 import com.android.tradefed.device.ITestDevice;
 import com.android.tradefed.device.TestDevice;
 import com.android.tradefed.log.LogUtil.CLog;
-import com.android.tradefed.result.FileInputStreamSource;
-import com.android.tradefed.result.LogDataType;
 import com.android.tradefed.testtype.junit4.BaseHostJUnit4Test;
 import com.android.tradefed.util.CommandResult;
 import com.android.tradefed.util.CommandStatus;
@@ -96,12 +94,7 @@
 
     public static void archiveLogThenDelete(TestLogData logs, ITestDevice device, String remotePath,
             String localName) throws DeviceNotAvailableException {
-        File logFile = device.pullFile(remotePath);
-        if (logFile != null) {
-            logs.addTestLog(localName, LogDataType.TEXT, new FileInputStreamSource(logFile));
-            // Delete to avoid confusing logs from a previous run, just in case.
-            device.deleteFile(remotePath);
-        }
+        LogArchiver.archiveLogThenDelete(logs, device, remotePath, localName);
     }
 
     // Run an arbitrary command in the host side and returns the result