cros_build_lib: Return a list from GetImageDiskPartitionInfo

BUG=None
TEST=Updated unit tests all pass

Change-Id: I25e3f78ebba00f692eb8981f4f7d9fff832feb8e
Reviewed-on: https://chromium-review.googlesource.com/1359008
Commit-Ready: LaMont Jones <lamontjones@chromium.org>
Tested-by: LaMont Jones <lamontjones@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_generate_update_payload_unittest.py b/scripts/cros_generate_update_payload_unittest.py
index ddcb6c9..35dfc00 100644
--- a/scripts/cros_generate_update_payload_unittest.py
+++ b/scripts/cros_generate_update_payload_unittest.py
@@ -77,10 +77,10 @@
     osutils.WriteFile(image, image_bin)
     part_a = os.path.join(self.tempdir, 'a.bin')
 
-    fake_partitions = {
-        'PART-A': cros_build_lib.PartitionInfo(1, 0, 4, 4, 'fs', 'PART-A', ''),
-        'PART-B': cros_build_lib.PartitionInfo(2, 4, 8, 4, 'fs', 'PART-B', ''),
-    }
+    fake_partitions = (
+        cros_build_lib.PartitionInfo(1, 0, 4, 4, 'fs', 'PART-A', ''),
+        cros_build_lib.PartitionInfo(2, 4, 8, 4, 'fs', 'PART-B', ''),
+    )
     self.PatchObject(cros_build_lib, 'GetImageDiskPartitionInfo',
                      return_value=fake_partitions)
 
@@ -105,9 +105,9 @@
     self.PatchObject(cros_generate_update_payload, 'Ext2FileSystemSize',
                      return_value=4)
 
-    fake_partitions = {
-        'ROOT-A': cros_build_lib.PartitionInfo(3, 0, 4, 4, 'fs', 'ROOT-A', ''),
-    }
+    fake_partitions = (
+        cros_build_lib.PartitionInfo(3, 0, 4, 4, 'fs', 'ROOT-A', ''),
+    )
     self.PatchObject(cros_build_lib, 'GetImageDiskPartitionInfo',
                      return_value=fake_partitions)
     cros_generate_update_payload.main([