Add option to preserve or unify line separators

README.md

@@ -58,12 +58,15 @@ These instructions will get you a copy of the project up and running on your loc
                                     keywords are left-aligned, and there is a
                                     single space between the step keyword and the
                                     statement.
+      -n, --newline [LF|CRLF]       Specify the line separators when formatting
+                                    files inplace. If not specified, line
+                                    separators are preserved.
       --fast / --safe               If --fast given, skip the sanity checks of
                                     file contents. [default: --safe]
       --config FILE                 Read configuration from FILE.
       --version                     Show the version and exit.
       --help                        Show this message and exit.
-      
+
 ### Config file
 
 The tool is able to read project-specific default values for its command line options from a `.reformat-gherkin.yaml` file.

reformat_gherkin/cli.py

@@ -5,7 +5,7 @@
 from .config import read_config_file
 from .core import reformat
 from .errors import EmptySources
-from .options import AlignmentMode, Options, WriteBackMode
+from .options import AlignmentMode, NewlineMode, Options, WriteBackMode
 from .report import Report
 from .utils import out
 from .version import __version__
@@ -41,6 +41,15 @@
         "space between the step keyword and the statement."
     ),
 )
+@click.option(
+    "-n",
+    "--newline",
+    type=click.Choice([NewlineMode.LF.value, NewlineMode.CRLF.value]),
+    help=(
+        "Specify the line separators when formatting files inplace. "
+        "If not specified, line separators are preserved."
+    ),
+)
 @click.option(
     "--fast/--safe",
     is_flag=True,
@@ -62,6 +71,7 @@ def main(
     src: Tuple[str],
     check: bool,
     alignment: Optional[str],
+    newline: Optional[str],
     fast: bool,
     config: Optional[str],
 ) -> None:
@@ -73,9 +83,13 @@ def main(
 
     write_back_mode = WriteBackMode.from_configuration(check)
     alignment_mode = AlignmentMode.from_configuration(alignment)
+    newline_mode = NewlineMode.from_configuration(newline)
 
     options = Options(
-        write_back=write_back_mode, step_keyword_alignment=alignment_mode, fast=fast
+        write_back=write_back_mode,
+        step_keyword_alignment=alignment_mode,
+        newline=newline_mode,
+        fast=fast,
     )
 
     report = Report(check=check)

reformat_gherkin/core.py

@@ -12,13 +12,15 @@
     StableError,
 )
 from .formatter import LineGenerator
-from .options import Options, WriteBackMode
+from .options import NewlineMode, Options, WriteBackMode
 from .parser import parse
 from .report import Report
 from .utils import decode_bytes, diff, dump_to_file, err
 
 REPORT_URL = "https://github.com/ducminh-phan/reformat-gherkin/issues"
 
+NEWLINE_FROM_OPTION = {NewlineMode.CRLF: "\r\n", NewlineMode.LF: "\n"}
+
 
 def find_sources(src: Tuple[str]) -> Set[Path]:
     sources: Set[Path] = set()
@@ -55,6 +57,8 @@ def reformat_single_file(path: Path, *, options: Options) -> bool:
     with open(path, "rb") as buf:
         src_contents, encoding, newline = decode_bytes(buf.read())
 
+    newline = NEWLINE_FROM_OPTION.get(options.newline, newline)
+
     try:
         dst_contents = format_file_contents(src_contents, options=options)
     except NothingChanged:

reformat_gherkin/options.py

@@ -25,8 +25,20 @@ def from_configuration(cls, alignment: Optional[str]) -> "AlignmentMode":
         return AlignmentMode(alignment)
 
 
-@dataclass(frozen=True, kw_only=True)
+@unique
+class NewlineMode(Enum):
+    KEEP = None
+    LF = "LF"
+    CRLF = "CRLF"
+
+    @classmethod
+    def from_configuration(cls, newline: Optional[str]) -> "NewlineMode":
+        return NewlineMode(newline)
+
+
+@dataclass(frozen=True)
 class Options:
     write_back: WriteBackMode
     step_keyword_alignment: AlignmentMode
+    newline: NewlineMode
     fast: bool

tests/conftest.py

@@ -83,6 +83,27 @@ def fin():
     return construct_sources
 
 
+@pytest.fixture
+def source_with_newline(request):
+    def construct_source_with_newline(newline):
+        tmp_file = Path(f"tmp{os.urandom(4).hex()}.feature")
+
+        with open(TEST_DIR / "data" / "valid" / "full.feature", "r") as f:
+            content = f.read()
+
+        with open(tmp_file, "w", newline=newline) as f:
+            f.write(content)
+
+        def fin():
+            os.remove(tmp_file)
+
+        request.addfinalizer(fin)
+
+        return tmp_file
+
+    return construct_source_with_newline
+
+
 @pytest.fixture
 def runner():
     return CliRunner()

tests/helpers.py

@@ -1,9 +1,10 @@
-from reformat_gherkin.options import AlignmentMode, Options, WriteBackMode
+from reformat_gherkin.options import AlignmentMode, NewlineMode, Options, WriteBackMode
 
 OPTIONS = [
     Options(
         write_back=WriteBackMode.CHECK,
         step_keyword_alignment=alignment_mode,
+        newline=NewlineMode.KEEP,
         fast=False,
     )
     for alignment_mode in AlignmentMode

tests/test_core.py

@@ -1,5 +1,6 @@
 from unittest.mock import patch
 
+import attr
 import pytest
 
 from reformat_gherkin import core
@@ -77,3 +78,36 @@ def test_format_file_contents_no_change(options):
 
     with pytest.raises(NothingChanged):
         core.format_file_contents(formatted_content, options=options)
+
+
+@pytest.mark.parametrize("newline_mode", core.NEWLINE_FROM_OPTION.keys())
+@pytest.mark.parametrize("newline", core.NEWLINE_FROM_OPTION.values())
+def test_line_separators_changed(source_with_newline, newline_mode, newline):
+    options = OPTIONS[0]
+    options = attr.evolve(
+        options, write_back=core.WriteBackMode.INPLACE, newline=newline_mode
+    )
+
+    source = source_with_newline(newline)
+
+    core.reformat_single_file(source, options=options)
+
+    with open(source, "rb") as buf:
+        _newline = core.decode_bytes(buf.read())[2]
+
+        assert _newline == core.NEWLINE_FROM_OPTION[newline_mode]
+
+
+@pytest.mark.parametrize("newline", core.NEWLINE_FROM_OPTION.values())
+def test_line_separators_preserved(source_with_newline, newline):
+    options = OPTIONS[0]
+    options = attr.evolve(options, write_back=core.WriteBackMode.INPLACE)
+
+    source = source_with_newline(newline)
+
+    core.reformat_single_file(source, options=options)
+
+    with open(source, "rb") as buf:
+        _newline = core.decode_bytes(buf.read())[2]
+
+        assert _newline == newline