Validation for --port, closes #1226

datasette/cli.py

@@ -223,6 +223,7 @@ def plugins(all, plugins_dir):
     "-p",
     "--port",
     default=8001,
+    type=click.IntRange(1, 65535),
     help="Port to run the server on, defaults to 8001",
 )
 @click.option("--title", help="Title for metadata")
@@ -329,6 +330,7 @@ def uninstall(packages, yes):
     "-p",
     "--port",
     default=8001,
+    type=click.IntRange(0, 65535),
     help="Port for server, defaults to 8001. Use -p 0 to automatically assign an available port.",
 )
 @click.option(

tests/test_cli.py

@@ -194,6 +194,14 @@ def test_version():
     assert result.output == f"cli, version {__version__}\n"
 
 
+@pytest.mark.parametrize("invalid_port", ["-1", "0.5", "dog", "65536"])
+def test_serve_invalid_ports(ensure_eventloop, invalid_port):
+    runner = CliRunner(mix_stderr=False)
+    result = runner.invoke(cli, ["--port", invalid_port])
+    assert result.exit_code == 2
+    assert "Invalid value for '-p'" in result.stderr
+
+
 def test_setting(ensure_eventloop):
     runner = CliRunner()
     result = runner.invoke(