delete-objects --dry-run option

docs/help.md

@@ -121,6 +121,7 @@ Usage: s3-credentials delete-objects [OPTIONS] BUCKET [KEYS]...
 Options:
   --prefix TEXT         Delete everything with this prefix
   -s, --silent          Don't show informational output
+  -d, --dry-run         Show keys that would be deleted without deleting them
   --access-key TEXT     AWS access key ID
   --secret-key TEXT     AWS secret access key
   --session-token TEXT  AWS session token

s3_credentials/cli.py

@@ -1342,8 +1342,15 @@ def get_cors_policy(bucket, **boto_options):
 @click.option(
     "silent", "-s", "--silent", is_flag=True, help="Don't show informational output"
 )
+@click.option(
+    "dry_run",
+    "-d",
+    "--dry-run",
+    is_flag=True,
+    help="Show keys that would be deleted without deleting them",
+)
 @common_boto3_options
-def delete_objects(bucket, keys, prefix, silent, **boto_options):
+def delete_objects(bucket, keys, prefix, silent, dry_run, **boto_options):
     """
     Delete one or more object from an S3 bucket
 
@@ -1374,6 +1381,11 @@ def delete_objects(bucket, keys, prefix, silent, **boto_options):
             ),
             err=True,
         )
+    if dry_run:
+        click.echo("The following keys would be deleted:")
+        for key in keys:
+            click.echo(key)
+        return
     for batch in batches(keys, 1000):
         response = s3.delete_objects(
             Bucket=bucket, Delete={"Objects": [{"Key": key} for key in batch]}

tests/test_s3_credentials.py

@@ -1248,3 +1248,31 @@ def test_delete_objects(moto_s3_populated, args, expected, expected_error):
                 or []
             }
             assert keys == set(expected)
+
+
+@pytest.mark.parametrize("arg", ("-d", "--dry-run"))
+def test_delete_objects_dry_run(moto_s3_populated, arg):
+    runner = CliRunner(mix_stderr=False)
+
+    def get_keys():
+        return {
+            obj["Key"]
+            for obj in moto_s3_populated.list_objects(Bucket="my-bucket").get(
+                "Contents"
+            )
+            or []
+        }
+
+    with runner.isolated_filesystem():
+        before_keys = get_keys()
+        result = runner.invoke(
+            cli, ["delete-objects", "my-bucket", "--prefix", "directory/", arg]
+        )
+        assert result.exit_code == 0
+        assert result.output == (
+            "The following keys would be deleted:\n"
+            "directory/three.json\n"
+            "directory/two.txt\n"
+        )
+        after_keys = get_keys()
+        assert before_keys == after_keys