Issue 4231 - Fix unstable FilterEngineTest.testSetRemoveFilterChangeCallback

libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/LazyFileSystem.java

Index: libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/LazyFileSystem.java
diff --git a/libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/LazyFileSystem.java b/libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/LazyFileSystem.java
new file mode 100644
index 0000000000000000000000000000000000000000..7a651a7e1ab728a8f994b7788f7ff47fd3407371
--- /dev/null
+++ b/libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/LazyFileSystem.java
@@ -0,0 +1,66 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.adblockplus.libadblockplus.tests;
+
+import org.adblockplus.libadblockplus.FileSystem;
+
+public class LazyFileSystem extends FileSystem
+{
+    @Override
+    public String read(String path)
+    {
+        if (path.equals("patterns.ini"))
+            return "# Adblock Plus preferences\n[Subscription]\nurl=~fl~";
+        else if (path.equals("prefs.json"))
+            return "{}";
+        else
+            return "";
+    }
+
+    @Override
+    public void write(String path, String data)
+    {
+
+    }
+
+    @Override
+    public void move(String fromPath, String toPath)
+    {
+
+    }
+
+    @Override
+    public void remove(String path)
+    {
+
+    }
+
+    @Override
+    public StatResult stat(String path)
+    {
+        return path.equals("patterns.ini")
+            ? new StatResult(true, false, true, 0)
+            : new StatResult(false, false, false, 0);
+    }
+
+    @Override
+    public String resolve(String path)
+    {
+        return path;
+    }
+}