feat(emit): make text param in open_stream() optional (#194)

craft_cli/messages.py

@@ -306,7 +306,7 @@ class _StreamContextManager:
     def __init__(  # noqa: PLR0913 (too many arguments)
         self,
         printer: Printer,
-        text: str,
+        text: str | None,
         stream: TextIO | None,
         use_timestamp: bool,  # noqa: FBT001 (boolean positional arg)
         ephemeral_mode: bool,  # noqa: FBT001 (boolean positional arg)
@@ -319,9 +319,10 @@ def __init__(  # noqa: PLR0913 (too many arguments)
             "end_line": not ephemeral_mode,
         }
 
-        # show the intended text (explicitly asking for a complete line) before passing the
-        # output command to the pip-reading thread
-        printer.show(stream, text, **printer_flags)
+        if text is not None:
+            # show the intended text (explicitly asking for a complete line) before
+            # passing the output command to the pipe-reading thread
+            printer.show(stream, text, **printer_flags)
 
         # enable the thread to read and show what comes through the provided pipe
         self.pipe_reader = _PipeReaderThread(printer, stream, printer_flags)
@@ -640,7 +641,7 @@ def progress_bar(
         return _Progresser(self._printer, total, text, stream, delta, use_timestamp, ephemeral)
 
     @_active_guard()
-    def open_stream(self, text: str) -> _StreamContextManager:
+    def open_stream(self, text: str | None = None) -> _StreamContextManager:
         """Open a stream context manager to get messages from subprocesses."""
         if self._mode == EmitterMode.QUIET:
             # no third party stream

tests/integration/test_messages_integration.py

@@ -1512,3 +1512,37 @@ def test_secrets_integrated(capsys, logger, monkeypatch, init_emitter):
         expected_err=expected_err,
         expected_log=expected_log,
     )
+
+
+@pytest.mark.parametrize("output_is_terminal", [True])
+def test_open_stream_no_text(capsys, logger, monkeypatch, init_emitter):
+    """Test emitter output when open_stream() has no `text` parameter"""
+    monkeypatch.setattr(printer, "_get_terminal_width", lambda: 200)
+
+    emit = Emitter()
+    emit.init(EmitterMode.VERBOSE, "testapp", GREETING)
+
+    emit.progress("Begin stage", permanent=False)
+
+    with emit.open_stream() as write_pipe:
+        os.write(write_pipe, b"Info message 1\n")
+        os.write(write_pipe, b"Info message 2\n")
+
+    emit.progress("End stage", permanent=False)
+    emit.ended_ok()
+
+    expected_err = [
+        Line("Begin stage"),
+        Line(":: Info message 1"),
+        Line(":: Info message 2"),
+        Line("End stage"),
+    ]
+    expected_log = expected_err
+
+    assert_outputs(
+        capsys,
+        emit,
+        expected_out=None,
+        expected_err=expected_err,
+        expected_log=expected_log,
+    )

tests/unit/test_messages_emitter.py

@@ -579,6 +579,28 @@ def test_openstream_in_developer_modes(get_initiated_emitter, mode):
     ]
 
 
+def test_openstream_no_text(get_initiated_emitter):
+    """Test open_stream() with no text parameter."""
+    emitter = get_initiated_emitter(EmitterMode.VERBOSE)
+
+    with patch("craft_cli.messages._StreamContextManager") as stream_context_manager_mock:
+        instantiated_cm = object()
+        stream_context_manager_mock.return_value = instantiated_cm
+        context_manager = emitter.open_stream()
+
+    assert emitter.printer_calls == []
+    assert context_manager is instantiated_cm
+    assert stream_context_manager_mock.mock_calls == [
+        call(
+            emitter._printer,
+            None,
+            stream=sys.stderr,
+            use_timestamp=False,
+            ephemeral_mode=False,
+        ),
+    ]
+
+
 @pytest.mark.parametrize(
     "mode",
     [