test_api_base: compare files using sha1

Instead of comparing files all the time using 'filecmp', calculate
sha1 of the image once and compare it to the copies.

This will be needed soon in order to implement compressed files testing - the
'filecmp' module does not accept file-like objects, only file names, so you
cannot feed it a compressed image.

Change-Id: I0c4db36fb89f9c5b8ba5aac116e9f25d9a17b4f6
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

diff --git a/tests/test_api_base.py b/tests/test_api_base.py
index 225e4f7..2cec130 100644 (file)
--- a/tests/test_api_base.py
+++ b/tests/test_api_base.py
@@ -10,6 +10,7 @@ file and the copy and verifies that they are identical. """
 
 import tempfile
 import filecmp
+import hashlib
 import unittest
 import itertools
 
@@ -37,6 +38,23 @@ def compare_holes(file1, file2):
             raise Error("mismatch for hole %d-%d, it is %d-%d in file2" \
                         % (range1[0], range1[1], range2[0], range2[1]))
 
+def _calculate_sha1(file_obj):
+    """ Calculates SHA1 checksum for the contents of file object
+    'file_obj'.  """
+
+    file_obj.seek(0)
+    hash_obj = hashlib.new("sha1")
+
+    chunk_size = 1024*1024
+
+    while True:
+        chunk = file_obj.read(chunk_size)
+        if not chunk:
+            break
+        hash_obj.update(chunk)
+
+    return hash_obj.hexdigest()
+
 def _do_test(f_image):
     """" A basic test for the bmap creation and copying functionality. It first
     generates a bmap for file object 'f_image', and then copies the sparse file
@@ -50,6 +68,8 @@ def _do_test(f_image):
     f_bmap1 = tempfile.NamedTemporaryFile("w+")
     f_bmap2 = tempfile.NamedTemporaryFile("w+")
 
+    image_sha1 = _calculate_sha1(f_image)
+
     #
     # Pass 1: generate the bmap, copy and compare
     #
@@ -63,7 +83,8 @@ def _do_test(f_image):
     writer.copy(False, True)
 
     # Compare the original file and the copy are identical
-    assert filecmp.cmp(f_image.name, f_copy.name, False)
+    assert _calculate_sha1(f_copy) == image_sha1
+
     # Make sure that holes in the copy are identical to holes in the random
     # sparse file.
     compare_holes(f_image.name, f_copy.name)
@@ -78,7 +99,7 @@ def _do_test(f_image):
     writer = BmapCopy.BmapCopy(f_image, f_copy, f_bmap2)
     writer.copy(False, True)
 
-    assert filecmp.cmp(f_image.name, f_copy.name, False)
+    assert _calculate_sha1(f_copy) == image_sha1
     compare_holes(f_image, f_copy)
 
     # Make sure the bmap files generated at pass 1 and pass 2 are identical
@@ -96,7 +117,7 @@ def _do_test(f_image):
     writer.copy(True, False)
     writer.copy(False, True)
     writer.sync()
-    assert filecmp.cmp(f_image.name, f_copy.name, False)
+    assert _calculate_sha1(f_copy) == image_sha1
     compare_holes(f_image, f_copy)
     assert filecmp.cmp(f_bmap1.name, f_bmap2.name, False)
 
@@ -107,11 +128,11 @@ def _do_test(f_image):
 
     writer = BmapCopy.BmapCopy(f_image, f_copy.name)
     writer.copy(True, True)
-    assert filecmp.cmp(f_image.name, f_copy.name, False)
+    assert _calculate_sha1(f_copy) == image_sha1
 
     writer = BmapCopy.BmapCopy(f_image, f_copy)
     writer.copy(False, True)
-    assert filecmp.cmp(f_image.name, f_copy.name, False)
+    assert _calculate_sha1(f_copy) == image_sha1
 
     # Close temporary files, which will also remove them
     f_copy.close()