Adding support for migrating the grid between any two valid screens sizes.

The grid is migrated in steps where each step consists of at max one column change and at max one row change.
Adding some unit tests for GridMigrationLogic

Bug: 25958224
Change-Id: Ie54e872ea0925cc4c463edbba0a7201d62b373a0

1 files changed, 40 insertions, 0 deletions

diff --git a/tests/src/com/android/launcher3/util/TestLauncherProvider.java b/tests/src/com/android/launcher3/util/TestLauncherProvider.java
new file mode 100644
index 000000000..aef3240ca
--- /dev/null
+++ b/tests/src/com/android/launcher3/util/TestLauncherProvider.java
@@ -0,0 +1,40 @@
+package com.android.launcher3.util;
+
+import android.content.Context;
+
+import com.android.launcher3.LauncherProvider;
+
+/**
+ * An extension of LauncherProvider backed up by in-memory database.
+ */
+public class TestLauncherProvider extends LauncherProvider {
+
+    @Override
+    public boolean onCreate() {
+        return true;
+    }
+
+    @Override
+    protected synchronized void createDbIfNotExists() {
+        if (mOpenHelper == null) {
+            mOpenHelper = new MyDatabaseHelper(getContext(), this);
+        }
+    }
+
+    @Override
+    protected void notifyListeners() { }
+
+    private static class MyDatabaseHelper extends DatabaseHelper {
+        public MyDatabaseHelper(Context context, LauncherProvider provider) {
+            super(context, provider, null);
+        }
+
+        @Override
+        protected long getDefaultUserSerial() {
+            return 0;
+        }
+
+        @Override
+        protected void onEmptyDbCreated() { }
+    }
+}
\ No newline at end of file