Add readlines method to Fs interface and implementations

- Add abstract readlines method to Fs class
- Implement readlines in PathFs using file.readlines()
- Implement readlines in RecordFs using splitlines(keepends=True)
- Add comprehensive tests for both implementations
- Test various scenarios: empty files, no final newline, different line endings

Author: cpyle0819

aws_doc_sdk_examples_tools/fs.py

@@ -27,6 +27,10 @@ def glob(self, path: Path, glob: str) -> Generator[Path, None, None]:
     def read(self, path: Path) -> str:
         pass
 
+    @abstractmethod
+    def readlines(self, path: Path) -> List[str]:
+        pass
+
     @abstractmethod
     def write(self, path: Path, content: str):
         pass
@@ -52,6 +56,10 @@ def read(self, path: Path) -> str:
         with path.open("r") as file:
             return file.read()
 
+    def readlines(self, path: Path) -> List[str]:
+        with path.open("r") as file:
+            return file.readlines()
+
     def write(self, path: Path, content: str):
         with path.open("w") as file:
             file.write(content)
@@ -87,6 +95,10 @@ def glob(self, path: Path, glob: str) -> Generator[Path, None, None]:
     def read(self, path: Path) -> str:
         return self.fs[path]
 
+    def readlines(self, path: Path) -> List[str]:
+        content = self.fs[path]
+        return content.splitlines(keepends=True)
+
     def write(self, path: Path, content: str):
         base = str(path.parent)
         assert any(

aws_doc_sdk_examples_tools/fs_test.py

@@ -0,0 +1,96 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""
+Tests for the Fs interface, particularly the readlines functionality.
+"""
+
+import pytest
+import tempfile
+from pathlib import Path
+from typing import List
+
+from .fs import Fs, PathFs, RecordFs
+
+
+def assert_readlines_result(fs: Fs, path: Path, expected: List[str]):
+    """Generic assertion for readlines results."""
+    lines = fs.readlines(path)
+    assert lines == expected
+    assert len(lines) == len(expected)
+
+
+def run_common_readlines_scenarios(fs: Fs, path_factory):
+    """Test common readlines scenarios for any Fs implementation."""
+    # Basic multi-line content
+    path = path_factory("Line 1\nLine 2\nLine 3\n")
+    assert_readlines_result(fs, path, ["Line 1\n", "Line 2\n", "Line 3\n"])
+
+    # Empty file
+    path = path_factory("")
+    assert_readlines_result(fs, path, [])
+
+    # No final newline
+    path = path_factory("Line 1\nLine 2")
+    assert_readlines_result(fs, path, ["Line 1\n", "Line 2"])
+
+    # Single line
+    path = path_factory("Single line\n")
+    assert_readlines_result(fs, path, ["Single line\n"])
+
+
+class TestPathFs:
+    """Test PathFs implementation of readlines."""
+
+    def test_readlines_scenarios(self):
+        """Test various readlines scenarios with PathFs."""
+        fs = PathFs()
+        temp_files = []
+
+        def path_factory(content: str) -> Path:
+            with tempfile.NamedTemporaryFile(
+                mode="w", delete=False, suffix=".txt"
+            ) as f:
+                f.write(content)
+                path = Path(f.name)
+                temp_files.append(path)
+                return path
+
+        try:
+            run_common_readlines_scenarios(fs, path_factory)
+        finally:
+            # Clean up temp files
+            for path in temp_files:
+                if path.exists():
+                    path.unlink()
+
+
+class TestRecordFs:
+    """Test RecordFs implementation of readlines."""
+
+    def test_readlines_scenarios(self):
+        """Test various readlines scenarios with RecordFs."""
+        test_cases = [
+            ("Line 1\nLine 2\nLine 3\n", ["Line 1\n", "Line 2\n", "Line 3\n"]),
+            ("", []),
+            ("Line 1\nLine 2", ["Line 1\n", "Line 2"]),
+            ("Single line\n", ["Single line\n"]),
+        ]
+
+        for content, expected in test_cases:
+            fs = RecordFs({Path("test.txt"): content})
+            assert_readlines_result(fs, Path("test.txt"), expected)
+
+    def test_readlines_line_ending_variations(self):
+        """Test readlines with different line ending styles."""
+        test_cases = [
+            (
+                "Line 1\r\nLine 2\r\nLine 3\r\n",
+                ["Line 1\r\n", "Line 2\r\n", "Line 3\r\n"],
+            ),
+            ("Line 1\nLine 2\r\nLine 3\n", ["Line 1\n", "Line 2\r\n", "Line 3\n"]),
+        ]
+
+        for content, expected in test_cases:
+            fs = RecordFs({Path("test.txt"): content})
+            assert_readlines_result(fs, Path("test.txt"), expected)