File Patch MCP Server

"""Test critical API semantics for Phase 2 tools. This test file verifies the CRITICAL API semantics as specified in the design: 1. validate_patch returns success=False when can_apply=False 2. inspect_patch returns files array (not file object) 3. apply_patch supports dry_run parameter 4. All tools use correct return formats """ import pytest from pathlib import Path from patch_mcp.tools.generate import generate_patch from patch_mcp.tools.inspect import inspect_patch from patch_mcp.tools.validate import validate_patch from patch_mcp.tools.apply import apply_patch from patch_mcp.tools.revert import revert_patch class TestCriticalAPISemantics: """Test suite for critical API semantics.""" def test_validate_patch_success_false_when_cannot_apply(self, tmp_path): """CRITICAL: validate_patch must return success=False when can_apply=False.""" # Create file with content that doesn't match patch file = tmp_path / "file.py" file.write_text("wrong\ncontent\n") # Patch expects different content patch = """--- file.py +++ file.py @@ -1,2 +1,2 @@ -expected +modified content """ result = validate_patch(str(file), patch) # CRITICAL: success must be False when cannot apply assert result["success"] is False, "success should be False when patch cannot be applied" assert result["valid"] is True, "patch format is valid" assert result["can_apply"] is False, "patch cannot be applied" assert result["error_type"] == "context_mismatch" assert "reason" in result, "reason must be present" assert isinstance(result["reason"], str) assert len(result["reason"]) > 0 assert "preview" in result, "preview should still be present" def test_validate_patch_success_true_when_can_apply(self, tmp_path): """validate_patch must return success=True when can_apply=True.""" file = tmp_path / "file.py" file.write_text("expected\ncontent\n") patch = """--- file.py +++ file.py @@ -1,2 +1,2 @@ -expected +modified content """ result = validate_patch(str(file), patch) # Success should be True when can apply assert result["success"] is True assert result["can_apply"] is True assert result["valid"] is True assert "preview" in result def test_inspect_patch_returns_files_array(self): """CRITICAL: inspect_patch must return files array, NOT file object.""" # Single file patch single_patch = """--- config.py +++ config.py @@ -1,1 +1,1 @@ -old +new """ result = inspect_patch(single_patch) # CRITICAL: Must return files array, not file object assert result["success"] is True assert "files" in result, "Must have 'files' field" assert "file" not in result, "Must NOT have 'file' field (old format)" assert isinstance(result["files"], list), "files must be a list/array" assert len(result["files"]) == 1, "Single file patch should have 1 element in array" # Verify file structure file_info = result["files"][0] assert "source" in file_info assert "target" in file_info assert "hunks" in file_info assert "lines_added" in file_info assert "lines_removed" in file_info # Verify summary exists assert "summary" in result assert result["summary"]["total_files"] == 1 def test_inspect_patch_multi_file_support(self): """inspect_patch must support multi-file patches.""" multi_patch = """--- file1.py +++ file1.py @@ -1,1 +1,1 @@ -old1 +new1 --- file2.py +++ file2.py @@ -1,1 +1,1 @@ -old2 +new2 """ result = inspect_patch(multi_patch) assert result["success"] is True assert len(result["files"]) == 2, "Multi-file patch should return all files" # Verify both files are present assert result["files"][0]["source"] == "file1.py" assert result["files"][1]["source"] == "file2.py" # Verify summary totals assert result["summary"]["total_files"] == 2 assert result["summary"]["total_hunks"] == 2 def test_apply_patch_dry_run_parameter(self, tmp_path): """CRITICAL: apply_patch must support dry_run parameter.""" file = tmp_path / "file.py" original = "line1\nline2\n" file.write_text(original) patch = """--- file.py +++ file.py @@ -1,2 +1,2 @@ -line1 +modified line2 """ # Test dry_run=True result = apply_patch(str(file), patch, dry_run=True) # Should succeed assert result["success"] is True assert result["applied"] is True assert "dry run" in result["message"].lower() # CRITICAL: File must NOT be modified assert file.read_text() == original, "dry_run must not modify file" # Test dry_run=False (default) result = apply_patch(str(file), patch, dry_run=False) assert result["success"] is True assert file.read_text() != original, "non-dry-run should modify file" def test_validate_affected_line_range_is_object(self, tmp_path): """affected_line_range must be an object with start/end, not a string.""" file = tmp_path / "file.py" file.write_text("line1\nline2\nline3\n") patch = """--- file.py +++ file.py @@ -1,3 +1,3 @@ -line1 +modified line2 line3 """ result = validate_patch(str(file), patch) assert result["success"] is True preview = result["preview"] # CRITICAL: affected_line_range must be an object, not a string assert "affected_line_range" in preview assert isinstance(preview["affected_line_range"], dict), "Must be object/dict, not string" assert "start" in preview["affected_line_range"] assert "end" in preview["affected_line_range"] assert isinstance(preview["affected_line_range"]["start"], int) assert isinstance(preview["affected_line_range"]["end"], int) def test_revert_patch_uses_reverted_field(self, tmp_path): """revert_patch must use 'reverted' field, not 'applied'.""" file = tmp_path / "file.py" file.write_text("original\n") patch = """--- file.py +++ file.py @@ -1,1 +1,1 @@ -original +modified """ # Apply then revert apply_patch(str(file), patch) result = revert_patch(str(file), patch) # Must use 'reverted' field assert "reverted" in result, "Must have 'reverted' field" assert "applied" not in result, "Should not have 'applied' field" assert result["reverted"] is True def test_all_tools_return_success_field(self, tmp_path): """All tools must return 'success' field.""" file1 = tmp_path / "file1.py" file2 = tmp_path / "file2.py" file1.write_text("content1\n") file2.write_text("content2\n") patch = """--- file1.py +++ file1.py @@ -1,1 +1,1 @@ -content1 +modified """ # Test all tools results = [ generate_patch(str(file1), str(file2)), inspect_patch(patch), validate_patch(str(file1), patch), apply_patch(str(file1), patch, dry_run=True), revert_patch(str(file1), patch), ] for result in results: assert "success" in result, "All tools must return 'success' field" assert isinstance(result["success"], bool) def test_all_failures_include_error_type(self, tmp_path): """All failures must include error_type field.""" missing = tmp_path / "missing.txt" patch = """--- missing.txt +++ missing.txt @@ -1,1 +1,1 @@ -old +new """ # Test error scenarios results = [ generate_patch(str(missing), str(missing)), validate_patch(str(missing), patch), apply_patch(str(missing), patch), revert_patch(str(missing), patch), ] for result in results: if not result["success"]: assert "error_type" in result, "Failed operations must include error_type" assert isinstance(result["error_type"], str) def test_empty_patch_handling(self, tmp_path): """All tools must handle empty patches correctly.""" file = tmp_path / "file.py" file.write_text("content\n") # Empty patch empty_patch = "" # inspect_patch result = inspect_patch(empty_patch) assert result["success"] is True assert result["files"] == [] assert result["summary"]["total_files"] == 0 # validate_patch result = validate_patch(str(file), empty_patch) assert result["success"] is True assert result["can_apply"] is True # apply_patch result = apply_patch(str(file), empty_patch) assert result["success"] is True assert result["changes"]["hunks_applied"] == 0 # revert_patch result = revert_patch(str(file), empty_patch) assert result["success"] is True class TestAPICompleteness: """Test that all required fields are present in responses.""" def test_generate_patch_complete_response(self, tmp_path): """generate_patch returns all required fields.""" file1 = tmp_path / "file1.txt" file2 = tmp_path / "file2.txt" file1.write_text("old\n") file2.write_text("new\n") result = generate_patch(str(file1), str(file2)) # Required fields assert "success" in result assert "original_file" in result assert "modified_file" in result assert "patch" in result assert "changes" in result assert "message" in result # Changes structure changes = result["changes"] assert "lines_added" in changes assert "lines_removed" in changes assert "hunks" in changes def test_inspect_patch_complete_response(self): """inspect_patch returns all required fields.""" patch = """--- file.py +++ file.py @@ -1,1 +1,1 @@ -old +new """ result = inspect_patch(patch) # Required fields assert "success" in result assert "valid" in result assert "files" in result assert "summary" in result assert "message" in result # Summary structure summary = result["summary"] assert "total_files" in summary assert "total_hunks" in summary assert "total_lines_added" in summary assert "total_lines_removed" in summary def test_validate_patch_complete_response(self, tmp_path): """validate_patch returns all required fields.""" file = tmp_path / "file.py" file.write_text("content\n") patch = """--- file.py +++ file.py @@ -1,1 +1,1 @@ -content +modified """ result = validate_patch(str(file), patch) # Required fields assert "success" in result assert "file_path" in result assert "valid" in result assert "can_apply" in result assert "preview" in result assert "message" in result # Preview structure preview = result["preview"] assert "lines_to_add" in preview assert "lines_to_remove" in preview assert "hunks" in preview assert "affected_line_range" in preview