better file comparing (#142)

* use sha1sum to compare files when syncing and verifying
* `load_installed_challenge` should throw an exception when it fails to load the challenge. This has been always assumed and there are checks before that call, but there's just no reason for it to return None instead of throwing.

Author: Miłosz Skaza

ctfcli/cli/challenges.py

@@ -14,7 +14,11 @@
 from ctfcli.core.challenge import Challenge
 from ctfcli.core.config import Config
 from ctfcli.core.deployment import get_deployment_handler
-from ctfcli.core.exceptions import ChallengeException, LintException
+from ctfcli.core.exceptions import (
+    ChallengeException,
+    LintException,
+    RemoteChallengeNotFound,
+)
 from ctfcli.utils.git import get_git_repo_head_branch
 
 log = logging.getLogger("ctfcli.cli.challenges")
@@ -774,8 +778,9 @@ def healthcheck(self, challenge: Optional[str] = None) -> int:
             )
             return 1
 
-        challenge_data = Challenge.load_installed_challenge(challenge_id)
-        if not challenge_data:
+        try:
+            challenge_data = Challenge.load_installed_challenge(challenge_id)
+        except RemoteChallengeNotFound:
             click.secho(f"Could not load data for challenge '{challenge_instance}'.", fg="red")
             return 1