# tests/unit/test_diff_util.py
# container-mcp © 2025 by Martin Bukowski is licensed under Apache 2.0
"""Unit tests for diff utility."""
import pytest
from cmcp.utils.diff import (
generate_diff,
apply_unified_diff,
split_patch_into_files,
analyze_diff,
DiffFormat
)
def test_generate_unified_diff():
"""Test generating a unified diff."""
original = """def hello():
print("Hello")
def world():
print("World")
"""
new = """def hello():
print("Hello")
def world():
print("World")
def goodbye():
print("Goodbye")
"""
diff_content, stats = generate_diff(original, new, DiffFormat.UNIFIED)
assert "def goodbye():" in diff_content
assert "+def goodbye():" in diff_content
assert stats.lines_added > 0
assert stats.lines_removed == 0
assert stats.hunks > 0
def test_apply_unified_diff():
"""Test applying a unified diff."""
original = """def hello():
print("Hello")
def world():
print("World")
"""
diff_content = """--- a/example.py
+++ b/example.py
@@ -4,2 +4,5 @@
def world():
print("World")
+
+def goodbye():
+ print("Goodbye")
"""
new_content, lines_applied = apply_unified_diff(original, diff_content)
assert "def goodbye():" in new_content
assert "print(\"Goodbye\")" in new_content
assert lines_applied > 0
def test_apply_diff_with_deletions():
"""Test applying a diff with deletions."""
original = """def hello():
print("Hello")
def world():
print("World")
def old_function():
print("Old")
"""
diff_content = """--- a/example.py
+++ b/example.py
@@ -5,4 +5,2 @@
print("World")
-def old_function():
- print("Old")
"""
new_content, lines_applied = apply_unified_diff(original, diff_content)
assert "def old_function():" not in new_content
assert "print(\"Old\")" not in new_content
assert lines_applied > 0
def test_split_patch_into_files():
"""Test splitting a multi-file patch."""
patch_content = """--- a/file1.py
+++ b/file1.py
@@ -1,3 +1,4 @@
def hello():
print("Hello")
+ return "hello"
--- a/file2.py
+++ b/file2.py
@@ -1,3 +1,4 @@
def world():
print("World")
+ return "world"
"""
file_diffs = split_patch_into_files(patch_content)
assert len(file_diffs) == 2
assert "file1.py" in file_diffs
assert "file2.py" in file_diffs
assert '+ return "hello"' in file_diffs["file1.py"]
assert '+ return "world"' in file_diffs["file2.py"]
def test_analyze_diff():
"""Test diff analysis."""
diff_content = """--- a/example.py
+++ b/example.py
@@ -1,5 +1,7 @@
def hello():
print("Hello")
+ # TODO: add more greetings
-def world():
- print("World")
+def world():
+ print("World!")
+ return "world"
"""
analysis = analyze_diff(diff_content)
assert "stats" in analysis
assert "patterns" in analysis
assert "complexity" in analysis
stats = analysis["stats"]
assert stats["lines_added"] > 0
assert stats["lines_removed"] > 0
assert stats["hunks"] > 0
patterns = analysis["patterns"]
assert patterns["comments_added"] > 0
assert len(patterns["potential_issues"]) > 0 # Should detect TODO
def test_generate_context_diff():
"""Test generating a context diff."""
original = "line1\nline2\nline3\n"
new = "line1\nline2 modified\nline3\n"
diff_content, stats = generate_diff(original, new, DiffFormat.CONTEXT)
assert "***" in diff_content
assert "---" in diff_content
# Context diffs show modifications as both removal and addition
assert stats.lines_modified > 0
assert stats.hunks > 0
def test_generate_ndiff():
"""Test generating an ndiff."""
original = "line1\nline2\nline3\n"
new = "line1\nline2 modified\nline3\n"
diff_content, stats = generate_diff(original, new, DiffFormat.NDIFF)
assert "- line2" in diff_content
assert "+ line2 modified" in diff_content
assert stats.lines_added > 0
assert stats.lines_removed > 0
def test_apply_diff_invalid_format():
"""Test applying an invalid diff format."""
original = "test content"
invalid_diff = "not a valid diff"
# Should handle gracefully and return original content
new_content, lines_applied = apply_unified_diff(original, invalid_diff)
assert new_content == original
assert lines_applied == 0
def test_apply_diff_context_mismatch():
"""Test applying a diff with context mismatch."""
original = """def hello():
print("Hello")
"""
# Diff expects different content
diff_content = """--- a/example.py
+++ b/example.py
@@ -1,2 +1,3 @@
def goodbye():
print("Goodbye")
+ return "goodbye"
"""
with pytest.raises(ValueError, match="Context mismatch"):
apply_unified_diff(original, diff_content)
