Auto convert content shell tests to JUnit4

content/public/android/javatests/src/org/chromium/content/browser/ImportantFileWriterAndroidTest.java

Index: content/public/android/javatests/src/org/chromium/content/browser/ImportantFileWriterAndroidTest.java
diff --git a/content/public/android/javatests/src/org/chromium/content/browser/ImportantFileWriterAndroidTest.java b/content/public/android/javatests/src/org/chromium/content/browser/ImportantFileWriterAndroidTest.java
index 5efe0c7e75625ecb86c313b59af95d7596fc0405..426147cab955ceaf0e49ec9abc3de5dfc114030e 100644
--- a/content/public/android/javatests/src/org/chromium/content/browser/ImportantFileWriterAndroidTest.java
+++ b/content/public/android/javatests/src/org/chromium/content/browser/ImportantFileWriterAndroidTest.java
@@ -1,14 +1,22 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.content.browser;
 
+import android.support.test.InstrumentationRegistry;
 import android.support.test.filters.SmallTest;
 
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
 import org.chromium.base.ImportantFileWriterAndroid;
+import org.chromium.base.test.BaseJUnit4ClassRunner;
 import org.chromium.base.test.util.Feature;
-import org.chromium.content.browser.test.NativeLibraryTestBase;
+import org.chromium.content.browser.test.NativeLibraryTestRule;
 
 import java.io.DataInputStream;
 import java.io.File;
@@ -23,62 +31,62 @@ import java.io.IOException;
  * work, so is not attempting to test that writes are atomic. Instead it is just
  * testing that the Java code is calling the native code correctly.
  */
-public class ImportantFileWriterAndroidTest extends NativeLibraryTestBase {
+@RunWith(BaseJUnit4ClassRunner.class)
+public class ImportantFileWriterAndroidTest {
+    @Rule
+    public NativeLibraryTestRule mActivityTestRule = new NativeLibraryTestRule();
 
     private void checkFile(File testFile, byte[] data) {
-        assertTrue(testFile.exists());
+        Assert.assertTrue(testFile.exists());
         try {
             byte[] fileData = new byte[(int) testFile.length()];
             DataInputStream dis =
                     new DataInputStream(new FileInputStream(testFile));
             dis.readFully(fileData);
             dis.close();
-            assertEquals("Data length wrong", data.length, fileData.length);
+            Assert.assertEquals("Data length wrong", data.length, fileData.length);
             for (int i = 0; i < data.length; i++) {
-                assertEquals("Data byte wrong", data[i], fileData[i]);
+                Assert.assertEquals("Data byte wrong", data[i], fileData[i]);
             }
         } catch (IOException e) {
-            fail("Failed to read file");
+            Assert.fail("Failed to read file");
         }
 
     }
 
+    @Test
     @SmallTest
     @Feature({"Android-AppBase"})
     public void testAtomicWrite() {
         // Try writing a file that can't be created.
         byte[] data1 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
-        assertFalse("Writing bad file succeded",
-                ImportantFileWriterAndroid.writeFileAtomically(
-                        "/junk/junk", data1));
-        File dir = getInstrumentation().getTargetContext().getFilesDir();
+        Assert.assertFalse("Writing bad file succeded",
+                ImportantFileWriterAndroid.writeFileAtomically("/junk/junk", data1));
+        File dir = InstrumentationRegistry.getInstrumentation().getTargetContext().getFilesDir();
         File testFile = new File(dir, "ImportantFileTest");
 
         // Make sure the file doesn't already exist
         if (testFile.exists()) {
-            assertTrue(testFile.delete());
+            Assert.assertTrue(testFile.delete());
         }
 
         // Write a new file
-        assertTrue("Writing new file failed",
-                ImportantFileWriterAndroid.writeFileAtomically(
-                        testFile.getAbsolutePath(), data1));
+        Assert.assertTrue("Writing new file failed",
+                ImportantFileWriterAndroid.writeFileAtomically(testFile.getAbsolutePath(), data1));
         checkFile(testFile, data1);
         byte[] data2 = {10, 20, 30, 40, 50, 60, 70, 80};
 
         // Overwrite an existing file
-        assertTrue("Writing exiting file failed",
-                ImportantFileWriterAndroid.writeFileAtomically(
-                        testFile.getAbsolutePath(), data2));
+        Assert.assertTrue("Writing exiting file failed",
+                ImportantFileWriterAndroid.writeFileAtomically(testFile.getAbsolutePath(), data2));
         checkFile(testFile, data2);
 
         // Done, tidy up
-        assertTrue(testFile.delete());
+        Assert.assertTrue(testFile.delete());
     }
 
-    @Override
+    @Before
     public void setUp() throws Exception {
-        super.setUp();
-        loadNativeLibraryNoBrowserProcess();
+        mActivityTestRule.loadNativeLibraryNoBrowserProcess();
     }
 }