test block patch more realistically

Read and write the same file when testing block patches, which can
turn up errors that don't show up otherwise.  (And will appear on the
device.)

Change-Id: Ic9b8d93ec980d13163b135f619af589f41433d7f

1 files changed, 4 insertions, 8 deletions

diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 9c10b68..87de2f6 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -837,7 +837,6 @@ def TestBlockPatch(src_muimg, src_map, patch_data, tgt_map, tgt_sha1):
 
   with tempfile.NamedTemporaryFile() as src_file,\
        tempfile.NamedTemporaryFile() as patch_file,\
-       tempfile.NamedTemporaryFile() as tgt_file,\
        tempfile.NamedTemporaryFile() as src_map_file,\
        tempfile.NamedTemporaryFile() as tgt_map_file:
 
@@ -853,20 +852,16 @@ def TestBlockPatch(src_muimg, src_map, patch_data, tgt_map, tgt_sha1):
 
     patch_file.write(patch_data)
 
-    tgt_total = sum(tgt_regions) * tgt_blksize
-    tgt_file.truncate(tgt_total)
-
     src_map_file.write(src_map)
     tgt_map_file.write(tgt_map)
 
     src_file.flush()
     src_map_file.flush()
     patch_file.flush()
-    tgt_file.flush()
     tgt_map_file.flush()
 
     p = common.Run(["syspatch_host", src_file.name, src_map_file.name,
-                    patch_file.name, tgt_file.name, tgt_map_file.name],
+                    patch_file.name, src_file.name, tgt_map_file.name],
                    stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     stdoutdata, _ = p.communicate()
     if p.returncode != 0:
@@ -874,10 +869,11 @@ def TestBlockPatch(src_muimg, src_map, patch_data, tgt_map, tgt_sha1):
       raise ValueError("failed to reconstruct target system image from patch")
 
     h = sha1()
+    src_file.seek(0, 0)
     for i in range(0, len(tgt_regions), 2):
       c, dc = tgt_regions[i:i+2]
-      h.update(tgt_file.read(c*tgt_blksize))
-      tgt_file.seek(dc*tgt_blksize, 1)
+      h.update(src_file.read(c*tgt_blksize))
+      src_file.seek(dc*tgt_blksize, 1)
 
     if h.hexdigest() != tgt_sha1:
       raise ValueError("patch reconstructed incorrect target system image")