diff --git a/.github/tests/test_dependabot_config.py b/.github/tests/test_dependabot_config.py
new file mode 100644
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+++ b/.github/tests/test_dependabot_config.py
@@ -0,0 +1,501 @@
+"""
+Comprehensive unit tests for dependabot configuration validation.
+Testing framework: pytest
+"""
+
+import os
+from pathlib import Path
+from typing import Any, Dict, List
+
+import pytest
+import yaml
+
+
+class TestDependabotConfig:
+    """Test suite for dependabot configuration validation."""
+
+    @pytest.fixture
+    def dependabot_config_path(self) -> Path:
+        """Fixture to provide the path to the dependabot configuration file."""
+        return Path(".github/dependabot.yml")
+
+    @pytest.fixture
+    def dependabot_config(self, dependabot_config_path: Path) -> Dict[str, Any]:
+        """Fixture to load and parse the dependabot configuration."""
+        if not dependabot_config_path.exists():
+            pytest.skip("Dependabot configuration file not found")
+
+        with dependabot_config_path.open("r") as f:
+            return yaml.safe_load(f)
+
+    def test_config_file_exists(self, dependabot_config_path: Path) -> None:
+        """Test that the dependabot configuration file exists."""
+        assert (
+            dependabot_config_path.exists()
+        ), "Dependabot configuration file should exist"
+
+    def test_config_file_is_valid_yaml(self, dependabot_config_path: Path) -> None:
+        """Test that the dependabot configuration file is valid YAML."""
+        try:
+            with dependabot_config_path.open("r") as f:
+                yaml.safe_load(f)
+        except yaml.YAMLError as e:
+            pytest.fail(f"Invalid YAML syntax: {e}")
+
+    def test_config_has_required_version_key(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that the configuration has the required 'version' key."""
+        assert "version" in dependabot_config, "Configuration must have 'version' key"
+
+    def test_config_version_is_supported(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that the configuration uses a supported version."""
+        supported_versions = [2]
+        version = dependabot_config.get("version")
+        assert version in supported_versions, (
+            f"Version {version} is not supported. "
+            f"Supported versions: {supported_versions}"
+        )
+
+    def test_config_has_updates_key(self, dependabot_config: Dict[str, Any]) -> None:
+        """Test that the configuration has the 'updates' key."""
+        assert "updates" in dependabot_config, "Configuration must have 'updates' key"
+
+    def test_updates_is_list(self, dependabot_config: Dict[str, Any]) -> None:
+        """Test that the 'updates' value is a list."""
+        updates = dependabot_config.get("updates", [])
+        assert isinstance(updates, list), "The 'updates' value must be a list"
+
+    def test_updates_list_not_empty(self, dependabot_config: Dict[str, Any]) -> None:
+        """Test that the updates list is not empty."""
+        updates = dependabot_config.get("updates", [])
+        assert updates, "The 'updates' list should not be empty"
+
+    def test_each_update_has_required_keys(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that each update entry has required keys."""
+        required_keys = ["package-ecosystem", "directory", "schedule"]
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            assert isinstance(update, dict), f"Update {i} must be a dictionary"
+            for key in required_keys:
+                assert key in update, f"Update {i} missing required key: {key}"
+
+    def test_package_ecosystem_values_are_valid(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that package-ecosystem values are valid."""
+        valid_ecosystems = [
+            "bundler",
+            "cargo",
+            "composer",
+            "docker",
+            "elm",
+            "gitsubmodule",
+            "github-actions",
+            "gomod",
+            "gradle",
+            "maven",
+            "mix",
+            "npm",
+            "nuget",
+            "pip",
+            "swift",
+            "terraform",
+        ]
+
+        updates = dependabot_config.get("updates", [])
+        for i, update in enumerate(updates):
+            ecosystem = update.get("package-ecosystem")
+            assert ecosystem in valid_ecosystems, (
+                f"Update {i} has invalid package-ecosystem: {ecosystem}"
+            )
+
+    def test_directory_values_are_valid_paths(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that directory values are valid paths."""
+        updates = dependabot_config.get("updates", [])
+        for i, update in enumerate(updates):
+            directory = update.get("directory")
+            assert isinstance(directory, str), f"Update {i} directory must be a string"
+            assert directory.startswith(
+                "/"
+            ), f"Update {i} directory must start with '/'"
+
+    def test_schedule_has_required_interval(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that each schedule has a required interval."""
+        updates = dependabot_config.get("updates", [])
+        for i, update in enumerate(updates):
+            schedule = update.get("schedule", {})
+            assert isinstance(
+                schedule, dict
+            ), f"Update {i} schedule must be a dictionary"
+            assert "interval" in schedule, f"Update {i} schedule missing 'interval' key"
+
+    def test_schedule_interval_values_are_valid(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that schedule interval values are valid."""
+        valid_intervals = ["daily", "weekly", "monthly"]
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            interval = update.get("schedule", {}).get("interval")
+            assert interval in valid_intervals, (
+                f"Update {i} has invalid schedule interval: {interval}"
+            )
+
+    def test_schedule_day_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that schedule day values are valid when present."""
+        valid_days = [
+            "monday",
+            "tuesday",
+            "wednesday",
+            "thursday",
+            "friday",
+            "saturday",
+            "sunday",
+        ]
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            schedule = update.get("schedule", {})
+            if "day" in schedule:
+                day = schedule["day"]
+                assert day in valid_days, f"Update {i} has invalid schedule day: {day}"
+
+    def test_schedule_time_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that schedule time values are in valid format when present."""
+        import re
+
+        time_pattern = re.compile(r"^([01]?[0-9]|2[0-3]):[0-5][0-9]$")
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            schedule = update.get("schedule", {})
+            if "time" in schedule:
+                time = schedule["time"]
+                assert isinstance(
+                    time, str
+                ), f"Update {i} schedule time must be a string"
+                assert time_pattern.match(
+                    time
+                ), f"Update {i} has invalid time format: {time}"
+
+    def test_schedule_timezone_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that schedule timezone values are valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            timezone = update.get("schedule", {}).get("timezone")
+            if timezone is not None:
+                assert isinstance(
+                    timezone, str
+                ), f"Update {i} schedule timezone must be a string"
+                assert timezone, f"Update {i} schedule timezone cannot be empty"
+
+    def test_open_pull_requests_limit_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that open-pull-requests-limit values are valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            if "open-pull-requests-limit" in update:
+                limit = update["open-pull-requests-limit"]
+                assert isinstance(
+                    limit, int
+                ), f"Update {i} open-pull-requests-limit must be an integer"
+                assert (
+                    0 <= limit <= 20
+                ), f"Update {i} open-pull-requests-limit must be between 0 and 20"
+
+    def test_target_branch_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that target-branch values are valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            if "target-branch" in update:
+                branch = update["target-branch"]
+                assert isinstance(
+                    branch, str
+                ), f"Update {i} target-branch must be a string"
+                assert branch, f"Update {i} target-branch cannot be empty"
+
+    def test_reviewers_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that reviewers format is valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            reviewers = update.get("reviewers")
+            if reviewers is not None:
+                assert isinstance(
+                    reviewers, list
+                ), f"Update {i} reviewers must be a list"
+                for reviewer in reviewers:
+                    assert isinstance(
+                        reviewer, str
+                    ), f"Update {i} reviewer must be a string"
+
+    def test_assignees_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that assignees format is valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            assignees = update.get("assignees")
+            if assignees is not None:
+                assert isinstance(
+                    assignees, list
+                ), f"Update {i} assignees must be a list"
+                for assignee in assignees:
+                    assert isinstance(
+                        assignee, str
+                    ), f"Update {i} assignee must be a string"
+
+    def test_labels_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that labels format is valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            labels = update.get("labels")
+            if labels is not None:
+                assert isinstance(labels, list), f"Update {i} labels must be a list"
+                for label in labels:
+                    assert isinstance(
+                        label, str
+                    ), f"Update {i} label must be a string"
+
+    def test_commit_message_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that commit-message format is valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            commit_message = update.get("commit-message")
+            if commit_message is not None:
+                assert isinstance(
+                    commit_message, dict
+                ), f"Update {i} commit-message must be a dictionary"
+
+                prefix = commit_message.get("prefix")
+                if prefix is not None:
+                    assert isinstance(
+                        prefix, str
+                    ), f"Update {i} commit-message prefix must be a string"
+
+                include = commit_message.get("include")
+                if include is not None:
+                    assert (
+                        include == "scope"
+                    ), f"Update {i} commit-message include must be 'scope'"
+
+    def test_rebase_strategy_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that rebase-strategy values are valid when present."""
+        valid_strategies = ["auto", "disabled"]
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            strategy = update.get("rebase-strategy")
+            if strategy is not None:
+                assert strategy in valid_strategies, (
+                    f"Update {i} has invalid rebase-strategy: {strategy}"
+                )
+
+    def test_allow_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that allow format is valid when present."""
+        valid_types = ["direct", "indirect", "all"]
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            allow = update.get("allow")
+            if allow is not None:
+                assert isinstance(allow, list), f"Update {i} allow must be a list"
+
+                for allow_item in allow:
+                    assert isinstance(
+                        allow_item, dict
+                    ), f"Update {i} allow item must be a dictionary"
+                    dep_type = allow_item.get("dependency-type")
+                    assert dep_type in valid_types, (
+                        f"Update {i} allow item has invalid dependency-type: {dep_type}"
+                    )
+
+    def test_ignore_format_is_valid_when_present(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that ignore format is valid when present."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            ignore = update.get("ignore")
+            if ignore is not None:
+                assert isinstance(
+                    ignore, list
+                ), f"Update {i} ignore must be a list"
+
+                for ignore_item in ignore:
+                    assert isinstance(
+                        ignore_item, dict
+                    ), f"Update {i} ignore item must be a dictionary"
+                    assert (
+                        "dependency-name" in ignore_item
+                    ), f"Update {i} ignore item must have 'dependency-name'"
+
+    def test_no_duplicate_package_ecosystem_directory_combinations(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that there are no duplicate package-ecosystem and directory combinations."""
+        updates = dependabot_config.get("updates", [])
+        combinations: List[Any] = []
+
+        for update in updates:
+            combo = (
+                update.get("package-ecosystem"),
+                update.get("directory"),
+            )
+            assert combo not in combinations, f"Duplicate combination found: {combo}"
+            combinations.append(combo)
+
+    def test_config_follows_best_practices(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that the configuration follows best practices."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            limit = update.get("open-pull-requests-limit")
+            if limit is not None:
+                assert (
+                    limit <= 10
+                ), f"Update {i} open-pull-requests-limit should be <= 10 for better management"
+
+    def test_config_has_security_updates_enabled(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that security updates are not explicitly disabled."""
+        updates = dependabot_config.get("updates", [])
+
+        for i, update in enumerate(updates):
+            limit = update.get("open-pull-requests-limit")
+            if limit is not None:
+                assert (
+                    limit > 0
+                ), f"Update {i} should allow at least one PR for security updates"
+
+    @pytest.mark.parametrize(
+        "ecosystem,expected_files",
+        [
+            ("npm", ["package.json"]),
+            (
+                "pip",
+                [
+                    "requirements.txt",
+                    "setup.py",
+                    "pyproject.toml",
+                ],
+            ),
+            ("docker", ["Dockerfile"]),
+            ("github-actions", [".github/workflows"]),
+        ],
+    )
+    def test_ecosystem_has_corresponding_files(
+        self,
+        dependabot_config: Dict[str, Any],
+        ecosystem: str,
+        expected_files: List[str],
+    ) -> None:
+        """Test that ecosystems have corresponding files in the repository."""
+        updates = dependabot_config.get("updates", [])
+        ecosystems_in_config = [
+            update.get("package-ecosystem") for update in updates
+        ]
+
+        if ecosystem in ecosystems_in_config:
+            for expected_file in expected_files:
+                file_path = Path(expected_file)
+                assert file_path.exists() or any(
+                    Path(".").glob(f"**/{expected_file}")
+                ), f"Expected file {expected_file} not found for ecosystem {ecosystem}"
+
+    def test_config_file_permissions(self, dependabot_config_path: Path) -> None:
+        """Test that the config file has appropriate permissions."""
+        import stat
+
+        file_stat = os.stat(dependabot_config_path)
+        mode = file_stat.st_mode
+
+        # Check that file is readable
+        assert mode & stat.S_IRUSR, "Config file should be readable by owner"
+        assert mode & stat.S_IRGRP, "Config file should be readable by group"
+        assert mode & stat.S_IROTH, "Config file should be readable by others"
+
+    def test_yaml_structure_depth_is_reasonable(
+        self, dependabot_config: Dict[str, Any]
+    ) -> None:
+        """Test that the YAML structure doesn't have excessive nesting."""
+
+        def get_max_depth(obj: Any, current_depth: int = 0) -> int:
+            if isinstance(obj, dict):
+                return max(
+                    [get_max_depth(v, current_depth + 1) for v in obj.values()]
+                    + [current_depth]
+                )
+            if isinstance(obj, list):
+                return max(
+                    [get_max_depth(item, current_depth + 1) for item in obj]
+                    + [current_depth]
+                )
+            return current_depth
+
+        max_depth = get_max_depth(dependabot_config)
+        assert (
+            max_depth <= 5
+        ), f"YAML structure is too deeply nested: {max_depth} levels"
+
+    def test_config_contains_no_sensitive_information(
+        self, dependabot_config_path: Path
+    ) -> None:
+        """Test that the config file doesn't contain sensitive information."""
+        sensitive_patterns = [
+            "password",
+            "secret",
+            "token",
+            "key",
+            "credential",
+            "auth",
+            "login",
+            "passwd",
+            "pass",
+        ]
+
+        content = dependabot_config_path.read_text().lower()
+        for pattern in sensitive_patterns:
+            assert (
+                pattern not in content
+            ), f"Potential sensitive information found: {pattern}"
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