Unittests for EntropyService. Make EntropyService more testable.

I've been meaning to write these tests for a long time...

Use "runtest frameworks-services" to run these tests.

Change-Id: I3a3cb7eda547f4a790f38be884b4a583426c7326

2 files changed, 57 insertions, 5 deletions

diff --git a/services/java/com/android/server/EntropyService.java b/services/java/com/android/server/EntropyService.java
index 0a53e9c..81ae26f 100644
--- a/services/java/com/android/server/EntropyService.java
+++ b/services/java/com/android/server/EntropyService.java
@@ -48,14 +48,15 @@ import android.util.Slog;
  * instead of periodically.
  */
 public class EntropyService extends Binder {
-    private static final String ENTROPY_FILENAME = getSystemDir() + "/entropy.dat";
     private static final String TAG = "EntropyService";
     private static final int ENTROPY_WHAT = 1;
     private static final int ENTROPY_WRITE_PERIOD = 3 * 60 * 60 * 1000;  // 3 hrs
-    private static final String RANDOM_DEV = "/dev/urandom";
     private static final long START_TIME = System.currentTimeMillis();
     private static final long START_NANOTIME = System.nanoTime();
 
+    private final String randomDevice;
+    private final String entropyFile;
+
     /**
      * Handler that periodically updates the entropy on disk.
      */
@@ -72,6 +73,16 @@ public class EntropyService extends Binder {
     };
 
     public EntropyService() {
+        this(getSystemDir() + "/entropy.dat", "/dev/urandom");
+    }
+
+    /** Test only interface, not for public use */
+    public EntropyService(String entropyFile, String randomDevice) {
+        if (randomDevice == null) { throw new NullPointerException("randomDevice"); }
+        if (entropyFile == null) { throw new NullPointerException("entropyFile"); }
+
+        this.randomDevice = randomDevice;
+        this.entropyFile = entropyFile;
         loadInitialEntropy();
         addDeviceSpecificEntropy();
         writeEntropy();
@@ -85,7 +96,7 @@ public class EntropyService extends Binder {
 
     private void loadInitialEntropy() {
         try {
-            RandomBlock.fromFile(ENTROPY_FILENAME).toFile(RANDOM_DEV);
+            RandomBlock.fromFile(entropyFile).toFile(randomDevice);
         } catch (IOException e) {
             Slog.w(TAG, "unable to load initial entropy (first boot?)", e);
         }
@@ -93,7 +104,7 @@ public class EntropyService extends Binder {
 
     private void writeEntropy() {
         try {
-            RandomBlock.fromFile(RANDOM_DEV).toFile(ENTROPY_FILENAME);
+            RandomBlock.fromFile(randomDevice).toFile(entropyFile);
         } catch (IOException e) {
             Slog.w(TAG, "unable to write entropy", e);
         }
@@ -116,7 +127,7 @@ public class EntropyService extends Binder {
     private void addDeviceSpecificEntropy() {
         PrintWriter out = null;
         try {
-            out = new PrintWriter(new FileOutputStream(RANDOM_DEV));
+            out = new PrintWriter(new FileOutputStream(randomDevice));
             out.println("Copyright (C) 2009 The Android Open Source Project");
             out.println("All Your Randomness Are Belong To Us");
             out.println(START_TIME);
diff --git a/services/tests/servicestests/src/com/android/server/EntropyServiceTest.java b/services/tests/servicestests/src/com/android/server/EntropyServiceTest.java
new file mode 100644
index 0000000..636ba21
--- /dev/null
+++ b/services/tests/servicestests/src/com/android/server/EntropyServiceTest.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2010 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 com.android.server;
+
+import android.content.Context;
+import android.os.FileUtils;
+import android.test.AndroidTestCase;
+
+import java.io.File;
+
+/**
+ * Tests for {@link com.android.server.EntropyService}
+ */
+public class EntropyServiceTest extends AndroidTestCase {
+
+    public void testInitialWrite() throws Exception {
+        File dir = getContext().getDir("testInitialWrite", Context.MODE_PRIVATE);
+        File file = File.createTempFile("testInitialWrite", "dat", dir);
+        file.deleteOnExit();
+        assertEquals(0, FileUtils.readTextFile(file, 0, null).length());
+
+        // The constructor has the side effect of writing to file
+        new EntropyService("/dev/null", file.getCanonicalPath());
+
+        assertTrue(FileUtils.readTextFile(file, 0, null).length() > 0);
+    }
+}