dump: learn to dump to stdout

Add the ability to dump to stdout when "-" is given as the filename.

src/gentoo_build_publisher/cli/dump.py

@@ -1,6 +1,7 @@
 """Dump builds to a file"""
 
 import argparse
+import sys
 
 from gbpcli.gbp import GBP
 from gbpcli.types import Console
@@ -23,15 +24,26 @@ def handler(args: argparse.Namespace, _gbp: GBP, console: Console) -> int:
         console.err.print(f"{error.args[0]} not found.")
         return 1
 
-    with open(args.filename, "wb") as fp:
+    filename = args.filename
+    is_stdout = filename == "-"
+
+    try:
+        # I'm using try/finally. Leave me alone pylint!
+        # pylint: disable=consider-using-with
+        fp = sys.stdout.buffer if is_stdout else open(filename, "wb")
         publisher.dump(builds, fp)
+    finally:
+        if not is_stdout:
+            fp.close()
 
     return 0
 
 
 def parse_args(parser: argparse.ArgumentParser) -> None:
     """Set subcommand arguments"""
-    parser.add_argument("filename", help="Filename to dump builds to")
+    parser.add_argument(
+        "filename", help='Filename to dump builds to ("-" for standard out)'
+    )
     parser.add_argument("machines", nargs="*", help="machine(s) to dump")
 
 

tests/test_cli_dump.py

@@ -2,6 +2,7 @@
 
 # pylint: disable=missing-docstring
 
+import io
 import json
 import tarfile as tar
 from pathlib import Path
@@ -73,6 +74,27 @@ def test_given_build(self) -> None:
 
         self.assertEqual(1, len(records(path)))
 
+    def test_dump_to_stdout(self) -> None:
+        create_builds()
+
+        cmdline = "gbp dump -"
+
+        args = parse_args(cmdline)
+        gbp = mock.Mock()
+        console = self.fixtures.console
+
+        with mock.patch("gentoo_build_publisher.cli.dump.sys.stdout") as stdout:
+            stdout.buffer = io.BytesIO()
+            status = dump(args, gbp, console)
+
+        self.assertEqual(0, status)
+        path = self.fixtures.tmpdir / "test.tar"
+
+        with open(path, "wb") as fp:
+            fp.write(stdout.buffer.getvalue())
+
+        self.assertEqual(6, len(records(path)))
+
     def test_build_id_not_found(self) -> None:
         create_builds()