[Qemu-block] [PULL 22/36] iotests/257: add Pattern class

[John Snow]

Just kidding, this is easier to manage with a full class instead of a
namedtuple.

Signed-off-by: John Snow <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
Message-id: address@hidden
Signed-off-by: John Snow <address@hidden>
---
 tests/qemu-iotests/257 | 58 +++++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 26 deletions(-)

diff --git a/tests/qemu-iotests/257 b/tests/qemu-iotests/257
index 39526837499..02f9ae06490 100755
--- a/tests/qemu-iotests/257
+++ b/tests/qemu-iotests/257
@@ -19,7 +19,6 @@
 #
 # owner=address@hidden
 
-from collections import namedtuple
 import math
 import os
 
@@ -29,10 +28,18 @@ from iotests import log, qemu_img
 SIZE = 64 * 1024 * 1024
 GRANULARITY = 64 * 1024
 
-Pattern = namedtuple('Pattern', ['byte', 'offset', 'size'])
-def mkpattern(byte, offset, size=GRANULARITY):
-    """Constructor for Pattern() with default size"""
-    return Pattern(byte, offset, size)
+
+class Pattern:
+    def __init__(self, byte, offset, size=GRANULARITY):
+        self.byte = byte
+        self.offset = offset
+        self.size = size
+
+    def bits(self, granularity):
+        lower = self.offset // granularity
+        upper = (self.offset + self.size - 1) // granularity
+        return set(range(lower, upper + 1))
+
 
 class PatternGroup:
     """Grouping of Pattern objects. Initialize with an iterable of Patterns."""
@@ -43,40 +50,39 @@ class PatternGroup:
         """Calculate the unique bits dirtied by this pattern grouping"""
         res = set()
         for pattern in self.patterns:
-            lower = pattern.offset // granularity
-            upper = (pattern.offset + pattern.size - 1) // granularity
-            res = res | set(range(lower, upper + 1))
+            res |= pattern.bits(granularity)
         return res
 
+
 GROUPS = [
     PatternGroup([
         # Batch 0: 4 clusters
-        mkpattern('0x49', 0x0000000),
-        mkpattern('0x6c', 0x0100000),   # 1M
-        mkpattern('0x6f', 0x2000000),   # 32M
-        mkpattern('0x76', 0x3ff0000)]), # 64M - 64K
+        Pattern('0x49', 0x0000000),
+        Pattern('0x6c', 0x0100000),   # 1M
+        Pattern('0x6f', 0x2000000),   # 32M
+        Pattern('0x76', 0x3ff0000)]), # 64M - 64K
     PatternGroup([
         # Batch 1: 6 clusters (3 new)
-        mkpattern('0x65', 0x0000000),   # Full overwrite
-        mkpattern('0x77', 0x00f8000),   # Partial-left (1M-32K)
-        mkpattern('0x72', 0x2008000),   # Partial-right (32M+32K)
-        mkpattern('0x69', 0x3fe0000)]), # Adjacent-left (64M - 128K)
+        Pattern('0x65', 0x0000000),   # Full overwrite
+        Pattern('0x77', 0x00f8000),   # Partial-left (1M-32K)
+        Pattern('0x72', 0x2008000),   # Partial-right (32M+32K)
+        Pattern('0x69', 0x3fe0000)]), # Adjacent-left (64M - 128K)
     PatternGroup([
         # Batch 2: 7 clusters (3 new)
-        mkpattern('0x74', 0x0010000),   # Adjacent-right
-        mkpattern('0x69', 0x00e8000),   # Partial-left  (1M-96K)
-        mkpattern('0x6e', 0x2018000),   # Partial-right (32M+96K)
-        mkpattern('0x67', 0x3fe0000,
-                  2*GRANULARITY)]),     # Overwrite [(64M-128K)-64M)
+        Pattern('0x74', 0x0010000),   # Adjacent-right
+        Pattern('0x69', 0x00e8000),   # Partial-left  (1M-96K)
+        Pattern('0x6e', 0x2018000),   # Partial-right (32M+96K)
+        Pattern('0x67', 0x3fe0000,
+                2*GRANULARITY)]),     # Overwrite [(64M-128K)-64M)
     PatternGroup([
         # Batch 3: 8 clusters (5 new)
         # Carefully chosen such that nothing re-dirties the one cluster
         # that copies out successfully before failure in Group #1.
-        mkpattern('0xaa', 0x0010000,
-                  3*GRANULARITY),       # Overwrite and 2x Adjacent-right
-        mkpattern('0xbb', 0x00d8000),   # Partial-left (1M-160K)
-        mkpattern('0xcc', 0x2028000),   # Partial-right (32M+160K)
-        mkpattern('0xdd', 0x3fc0000)]), # New; leaving a gap to the right
+        Pattern('0xaa', 0x0010000,
+                3*GRANULARITY),       # Overwrite and 2x Adjacent-right
+        Pattern('0xbb', 0x00d8000),   # Partial-left (1M-160K)
+        Pattern('0xcc', 0x2028000),   # Partial-right (32M+160K)
+        Pattern('0xdd', 0x3fc0000)]), # New; leaving a gap to the right
 ]
 
 class Drive:
-- 
2.21.0