diffoscope/comparators/xz.py

@@ -56,7 +56,7 @@ class XzContainer(Archive):
 class XzFile(File):
     DESCRIPTION = "XZ compressed files"
     CONTAINER_CLASSES = [XzContainer]
-    FILE_TYPE_RE = re.compile(r"^XZ compressed data$")
+    FILE_TYPE_RE = re.compile(r"^XZ compressed data\b")
 
     # Work around file(1) Debian bug #876316
     FALLBACK_FILE_EXTENSION_SUFFIX = {".xz"}

tests/comparators/test_containers.py

@@ -24,6 +24,7 @@ import itertools
 from ..utils.data import load_fixture, get_data
 from ..utils.tools import (
     skip_unless_tools_exist,
+    file_version_is_ge,
     skip_unless_file_version_is_at_least,
 )
 
@@ -50,9 +51,18 @@ def set2(gzip2, bzip2, xz2):
 
 
 def expected_magic_diff(ext1, ext2):
-    meta1 = get_data("containers/magic_%s" % ext1)
-    meta2 = get_data("containers/magic_%s" % ext2)
-    return "@@ -1 +1 @@\n" + "-" + meta1 + "+" + meta2
+    magic = {
+        "bzip2": "bzip2 compressed data, block size = 900k\n",
+        "gzip": "gzip compressed data, last modified: Sun Sep 10 22:19:44 2017, from Unix\n",
+        "xz": "XZ compressed data",
+    }
+    if "xz" in (ext1, ext2):
+        if file_version_is_ge("5.40"):
+            magic["xz"] += ", checksum CRC64\n"
+        else:
+            magic["xz"] += "\n"
+
+    return "@@ -1 +1 @@\n" + "-" + magic[ext1] + "+" + magic[ext2]
 
 
 def expected_type_diff(ext1, ext2):

tests/data/containers/magic_bzip2

-bzip2 compressed data, block size = 900k

tests/data/containers/magic_gzip

-gzip compressed data, last modified: Sun Sep 10 22:19:44 2017, from Unix

tests/data/containers/magic_xz

-XZ compressed data