servers-modelcontextprotocol/src/git/tests/test_server.py

import pytest
from pathlib import Path
import git
from git.exc import BadName
from mcp_server_git.server import (
    git_checkout,
    git_branch,
    git_add,
    git_status,
    git_diff_unstaged,
    git_diff_staged,
    git_diff,
    git_commit,
    git_reset,
    git_log,
    git_create_branch,
    git_show,
    validate_repo_path,
)
import shutil

@pytest.fixture
def test_repository(tmp_path: Path):
    repo_path = tmp_path / "temp_test_repo"
    test_repo = git.Repo.init(repo_path)

    Path(repo_path / "test.txt").write_text("test")
    test_repo.index.add(["test.txt"])
    test_repo.index.commit("initial commit")

    yield test_repo

    shutil.rmtree(repo_path)

def test_git_checkout_existing_branch(test_repository):
    test_repository.git.branch("test-branch")
    result = git_checkout(test_repository, "test-branch")

    assert "Switched to branch 'test-branch'" in result
    assert test_repository.active_branch.name == "test-branch"

def test_git_checkout_nonexistent_branch(test_repository):

    with pytest.raises(BadName):
        git_checkout(test_repository, "nonexistent-branch")

def test_git_branch_local(test_repository):
    test_repository.git.branch("new-branch-local")
    result = git_branch(test_repository, "local")
    assert "new-branch-local" in result

def test_git_branch_remote(test_repository):
    result = git_branch(test_repository, "remote")
    assert "" == result.strip()  # Should be empty if no remote branches

def test_git_branch_all(test_repository):
    test_repository.git.branch("new-branch-all")
    result = git_branch(test_repository, "all")
    assert "new-branch-all" in result

def test_git_branch_contains(test_repository):
    # Get the default branch name (could be "main" or "master")
    default_branch = test_repository.active_branch.name
    # Create a new branch and commit to it
    test_repository.git.checkout("-b", "feature-branch")
    Path(test_repository.working_dir / Path("feature.txt")).write_text("feature content")
    test_repository.index.add(["feature.txt"])
    commit = test_repository.index.commit("feature commit")
    test_repository.git.checkout(default_branch)

    result = git_branch(test_repository, "local", contains=commit.hexsha)
    assert "feature-branch" in result
    assert default_branch not in result

def test_git_branch_not_contains(test_repository):
    # Get the default branch name (could be "main" or "master")
    default_branch = test_repository.active_branch.name
    # Create a new branch and commit to it
    test_repository.git.checkout("-b", "another-feature-branch")
    Path(test_repository.working_dir / Path("another_feature.txt")).write_text("another feature content")
    test_repository.index.add(["another_feature.txt"])
    commit = test_repository.index.commit("another feature commit")
    test_repository.git.checkout(default_branch)

    result = git_branch(test_repository, "local", not_contains=commit.hexsha)
    assert "another-feature-branch" not in result
    assert default_branch in result

def test_git_add_all_files(test_repository):
    file_path = Path(test_repository.working_dir) / "all_file.txt"
    file_path.write_text("adding all")

    result = git_add(test_repository, ["."])

    staged_files = [item.a_path for item in test_repository.index.diff("HEAD")]
    assert "all_file.txt" in staged_files
    assert result == "Files staged successfully"

def test_git_add_specific_files(test_repository):
    file1 = Path(test_repository.working_dir) / "file1.txt"
    file2 = Path(test_repository.working_dir) / "file2.txt"
    file1.write_text("file 1 content")
    file2.write_text("file 2 content")

    result = git_add(test_repository, ["file1.txt"])

    staged_files = [item.a_path for item in test_repository.index.diff("HEAD")]
    assert "file1.txt" in staged_files
    assert "file2.txt" not in staged_files
    assert result == "Files staged successfully"

def test_git_status(test_repository):
    result = git_status(test_repository)

    assert result is not None
    assert "On branch" in result or "branch" in result.lower()

def test_git_diff_unstaged(test_repository):
    file_path = Path(test_repository.working_dir) / "test.txt"
    file_path.write_text("modified content")

    result = git_diff_unstaged(test_repository)

    assert "test.txt" in result
    assert "modified content" in result

def test_git_diff_unstaged_empty(test_repository):
    result = git_diff_unstaged(test_repository)

    assert result == ""

def test_git_diff_staged(test_repository):
    file_path = Path(test_repository.working_dir) / "staged_file.txt"
    file_path.write_text("staged content")
    test_repository.index.add(["staged_file.txt"])

    result = git_diff_staged(test_repository)

    assert "staged_file.txt" in result
    assert "staged content" in result

def test_git_diff_staged_empty(test_repository):
    result = git_diff_staged(test_repository)

    assert result == ""

def test_git_diff(test_repository):
    # Get the default branch name (could be "main" or "master")
    default_branch = test_repository.active_branch.name
    test_repository.git.checkout("-b", "feature-diff")
    file_path = Path(test_repository.working_dir) / "test.txt"
    file_path.write_text("feature changes")
    test_repository.index.add(["test.txt"])
    test_repository.index.commit("feature commit")

    result = git_diff(test_repository, default_branch)

    assert "test.txt" in result
    assert "feature changes" in result

def test_git_commit(test_repository):
    file_path = Path(test_repository.working_dir) / "commit_test.txt"
    file_path.write_text("content to commit")
    test_repository.index.add(["commit_test.txt"])

    result = git_commit(test_repository, "test commit message")

    assert "Changes committed successfully with hash" in result

    latest_commit = test_repository.head.commit
    assert latest_commit.message.strip() == "test commit message"

def test_git_reset(test_repository):
    file_path = Path(test_repository.working_dir) / "reset_test.txt"
    file_path.write_text("content to reset")
    test_repository.index.add(["reset_test.txt"])

    staged_before = [item.a_path for item in test_repository.index.diff("HEAD")]
    assert "reset_test.txt" in staged_before

    result = git_reset(test_repository)

    assert result == "All staged changes reset"

    staged_after = [item.a_path for item in test_repository.index.diff("HEAD")]
    assert "reset_test.txt" not in staged_after

def test_git_log(test_repository):
    for i in range(3):
        file_path = Path(test_repository.working_dir) / f"log_test_{i}.txt"
        file_path.write_text(f"content {i}")
        test_repository.index.add([f"log_test_{i}.txt"])
        test_repository.index.commit(f"commit {i}")

    result = git_log(test_repository, max_count=2)

    assert isinstance(result, list)
    assert len(result) == 2
    assert "Commit:" in result[0]
    assert "Author:" in result[0]
    assert "Date:" in result[0]
    assert "Message:" in result[0]

def test_git_log_default(test_repository):
    result = git_log(test_repository)

    assert isinstance(result, list)
    assert len(result) >= 1
    assert "initial commit" in result[0]

def test_git_create_branch(test_repository):
    result = git_create_branch(test_repository, "new-feature-branch")

    assert "Created branch 'new-feature-branch'" in result

    branches = [ref.name for ref in test_repository.references]
    assert "new-feature-branch" in branches

def test_git_create_branch_from_base(test_repository):
    test_repository.git.checkout("-b", "base-branch")
    file_path = Path(test_repository.working_dir) / "base.txt"
    file_path.write_text("base content")
    test_repository.index.add(["base.txt"])
    test_repository.index.commit("base commit")

    result = git_create_branch(test_repository, "derived-branch", "base-branch")

    assert "Created branch 'derived-branch' from 'base-branch'" in result

def test_git_show(test_repository):
    file_path = Path(test_repository.working_dir) / "show_test.txt"
    file_path.write_text("show content")
    test_repository.index.add(["show_test.txt"])
    test_repository.index.commit("show test commit")

    commit_sha = test_repository.head.commit.hexsha

    result = git_show(test_repository, commit_sha)

    assert "Commit:" in result
    assert "Author:" in result
    assert "show test commit" in result
    assert "show_test.txt" in result

def test_git_show_initial_commit(test_repository):
    initial_commit = list(test_repository.iter_commits())[-1]

    result = git_show(test_repository, initial_commit.hexsha)

    assert "Commit:" in result
    assert "initial commit" in result
    assert "test.txt" in result


# Tests for validate_repo_path (repository scoping security fix)

def test_validate_repo_path_no_restriction():
    """When no repository restriction is configured, any path should be allowed."""
    validate_repo_path(Path("/any/path"), None)  # Should not raise


def test_validate_repo_path_exact_match(tmp_path: Path):
    """When repo_path exactly matches allowed_repository, validation should pass."""
    allowed = tmp_path / "repo"
    allowed.mkdir()
    validate_repo_path(allowed, allowed)  # Should not raise


def test_validate_repo_path_subdirectory(tmp_path: Path):
    """When repo_path is a subdirectory of allowed_repository, validation should pass."""
    allowed = tmp_path / "repo"
    allowed.mkdir()
    subdir = allowed / "subdir"
    subdir.mkdir()
    validate_repo_path(subdir, allowed)  # Should not raise


def test_validate_repo_path_outside_allowed(tmp_path: Path):
    """When repo_path is outside allowed_repository, validation should raise ValueError."""
    allowed = tmp_path / "allowed_repo"
    allowed.mkdir()
    outside = tmp_path / "other_repo"
    outside.mkdir()

    with pytest.raises(ValueError) as exc_info:
        validate_repo_path(outside, allowed)
    assert "outside the allowed repository" in str(exc_info.value)


def test_validate_repo_path_traversal_attempt(tmp_path: Path):
    """Path traversal attempts (../) should be caught and rejected."""
    allowed = tmp_path / "allowed_repo"
    allowed.mkdir()
    # Attempt to escape via ../
    traversal_path = allowed / ".." / "other_repo"

    with pytest.raises(ValueError) as exc_info:
        validate_repo_path(traversal_path, allowed)
    assert "outside the allowed repository" in str(exc_info.value)


def test_validate_repo_path_symlink_escape(tmp_path: Path):
    """Symlinks pointing outside allowed_repository should be rejected."""
    allowed = tmp_path / "allowed_repo"
    allowed.mkdir()
    outside = tmp_path / "outside"
    outside.mkdir()

    # Create a symlink inside allowed that points outside
    symlink = allowed / "escape_link"
    symlink.symlink_to(outside)

    with pytest.raises(ValueError) as exc_info:
        validate_repo_path(symlink, allowed)
    assert "outside the allowed repository" in str(exc_info.value)
# Tests for argument injection protection

def test_git_diff_rejects_flag_injection(test_repository):
    """git_diff should reject flags that could be used for argument injection."""
    with pytest.raises(BadName):
        git_diff(test_repository, "--output=/tmp/evil")

    with pytest.raises(BadName):
        git_diff(test_repository, "--help")

    with pytest.raises(BadName):
        git_diff(test_repository, "-p")


def test_git_checkout_rejects_flag_injection(test_repository):
    """git_checkout should reject flags that could be used for argument injection."""
    with pytest.raises(BadName):
        git_checkout(test_repository, "--help")

    with pytest.raises(BadName):
        git_checkout(test_repository, "--orphan=evil")

    with pytest.raises(BadName):
        git_checkout(test_repository, "-f")


def test_git_diff_allows_valid_refs(test_repository):
    """git_diff should work normally with valid git refs."""
    # Get the default branch name
    default_branch = test_repository.active_branch.name

    # Create a branch with a commit for diffing
    test_repository.git.checkout("-b", "valid-diff-branch")
    file_path = Path(test_repository.working_dir) / "test.txt"
    file_path.write_text("valid diff content")
    test_repository.index.add(["test.txt"])
    test_repository.index.commit("valid diff commit")

    # Test with branch name
    result = git_diff(test_repository, default_branch)
    assert "test.txt" in result

    # Test with HEAD~1
    result = git_diff(test_repository, "HEAD~1")
    assert "test.txt" in result

    # Test with commit hash
    commit_sha = test_repository.head.commit.hexsha
    result = git_diff(test_repository, commit_sha)
    assert result is not None


def test_git_checkout_allows_valid_branches(test_repository):
    """git_checkout should work normally with valid branch names."""
    # Get the default branch name
    default_branch = test_repository.active_branch.name

    # Create a branch to checkout
    test_repository.git.branch("valid-checkout-branch")

    result = git_checkout(test_repository, "valid-checkout-branch")
    assert "Switched to branch 'valid-checkout-branch'" in result
    assert test_repository.active_branch.name == "valid-checkout-branch"

    # Checkout back to default branch
    result = git_checkout(test_repository, default_branch)
    assert "Switched to branch" in result
    assert test_repository.active_branch.name == default_branch


def test_git_diff_rejects_malicious_refs(test_repository):
    """git_diff should reject refs starting with '-' even if they exist.

    This tests defense in depth against an attacker who creates malicious
    refs via filesystem manipulation (e.g. using mcp-filesystem to write
    to .git/refs/heads/--output=...).
    """
    import os

    # Manually create a malicious ref by writing directly to .git/refs
    sha = test_repository.head.commit.hexsha
    refs_dir = Path(test_repository.git_dir) / "refs" / "heads"
    malicious_ref_path = refs_dir / "--output=evil.txt"
    malicious_ref_path.write_text(sha)

    # Even though the ref exists, it should be rejected
    with pytest.raises(BadName):
        git_diff(test_repository, "--output=evil.txt")

    # Verify no file was created (the attack was blocked)
    assert not os.path.exists("evil.txt")

    # Cleanup
    malicious_ref_path.unlink()


def test_git_checkout_rejects_malicious_refs(test_repository):
    """git_checkout should reject refs starting with '-' even if they exist."""
    # Manually create a malicious ref
    sha = test_repository.head.commit.hexsha
    refs_dir = Path(test_repository.git_dir) / "refs" / "heads"
    malicious_ref_path = refs_dir / "--orphan=evil"
    malicious_ref_path.write_text(sha)

    # Even though the ref exists, it should be rejected
    with pytest.raises(BadName):
        git_checkout(test_repository, "--orphan=evil")

    # Cleanup
    malicious_ref_path.unlink()