1 files changed, 16 insertions, 5 deletions
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 4afe63d..9351f9c 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -507,11 +507,22 @@ def qemu_nbd_popen(*args):
             p.kill()
             p.wait()
 
-def compare_images(img1, img2, fmt1=imgfmt, fmt2=imgfmt):
-    '''Return True if two image files are identical'''
-    res = qemu_img('compare', '-f', fmt1,
-                   '-F', fmt2, img1, img2, check=False)
-    return res.returncode == 0
+def compare_images(img1: str, img2: str,
+                   fmt1: str = imgfmt, fmt2: str = imgfmt) -> bool:
+    """
+    Compare two images with QEMU_IMG; return True if they are identical.
+
+    :raise CalledProcessError:
+        when qemu-img crashes or returns a status code of anything other
+        than 0 (identical) or 1 (different).
+    """
+    try:
+        qemu_img('compare', '-f', fmt1, '-F', fmt2, img1, img2)
+        return True
+    except subprocess.CalledProcessError as exc:
+        if exc.returncode == 1:
+            return False
+        raise
 
 def create_image(name, size):
     '''Create a fully-allocated raw image with sector markers'''