diff --git a/contrib_688_support_multi_file_rst_test_cases.py b/contrib_688_support_multi_file_rst_test_cases.py
new file mode 100644
index 000000000..eb50f3248
--- /dev/null
+++ b/contrib_688_support_multi_file_rst_test_cases.py
@@ -0,0 +1,181 @@
+# Support multi-file RST test cases (fix for issue #688)
+
+```python
+import os
+import shutil
+import tempfile
+import subprocess
+import re
+from pathlib import Path
+from typing import List, Tuple, Optional, Dict, Any
+from dataclasses import dataclass
+
+@dataclass
+class TestResult:
+    success: bool
+    warnings: List[Tuple[str, int, str]]  # (filename, line_number, message)
+    error: Optional[str] = None
+
+class RSTTestRunner:
+    """Supports both single-file and multi-file RST test cases for Sphinx validation."""
+    
+    def __init__(self, srcdir: str = None):
+        self.srcdir = srcdir or os.path.dirname(os.path.abspath(__file__))
+        self.build_dir = None
+        
+    def _is_multifile_testcase(self, testcase_path: Path) -> bool:
+        """Check if testcase is a directory with index.rst or contains multiple .rst files."""
+        if testcase_path.is_dir():
+            return (testcase_path / "index.rst").exists() or \
+                   len(list(testcase_path.glob("*.rst"))) > 1
+        return False
+    
+    def _copy_testcase_to_temp(self, testcase_path: Path, temp_dir: Path) -> Path:
+        """Copy testcase (file or directory) to temporary directory."""
+        if testcase_path.is_dir():
+            dest = temp_dir / testcase_path.name
+            shutil.copytree(testcase_path, dest)
+            return dest
+        else:
+            dest = temp_dir / testcase_path.name
+            shutil.copy2(testcase_path, dest)
+            return dest
+    
+    def _build_sphinx_project(self, src_path: Path, build_path: Path) -> TestResult:
+        """Build Sphinx project and collect warnings."""
+        try:
+            # Ensure build directory exists
+            build_path.mkdir(parents=True, exist_ok=True)
+            
+            # Run Sphinx build
+            result = subprocess.run(
+                [
+                    "sphinx-build",
+                    "-b", "html",
+                    "-W",  # Turn warnings into errors for validation
+                    str(src_path),
+                    str(build_path)
+                ],
+                capture_output=True,
+                text=True,
+                timeout=60
+            )
+            
+            # Parse warnings from stderr
+            warnings = self._parse_sphinx_warnings(result.stderr)
+            
+            # Return success if no warnings (since we use -W)
+            return TestResult(
+                success=result.returncode == 0,
+                warnings=warnings,
+                error=None if result.returncode == 0 else result.stderr
+            )
+            
+        except subprocess.TimeoutExpired:
+            return TestResult(
+                success=False,
+                warnings=[],
+                error="Sphinx build timed out"
+            )
+        except Exception as e:
+            return TestResult(
+                success=False,
+                warnings=[],
+                error=str(e)
+            )
+    
+    def _parse_sphinx_warnings(self, stderr: str) -> List[Tuple[str, int, str]]:
+        """Parse Sphinx warnings into structured format."""
+        warnings = []
+        # Pattern matches: path/to/file.rst:line: severity: message
+        pattern = r'([^:]+):(\d+):\s*(\w+):\s*(.+)'
+        
+        for line in stderr.split('\n'):
+            match = re.search(pattern, line)
+            if match:
+                filepath, lineno, severity, message = match.groups()
+                # Extract just the filename for clarity
+                filename = os.path.basename(filepath)
+                warnings.append((filename, int(lineno), f"{severity}: {message}"))
+        
+        return warnings
+    
+    def run_single_file_test(self, rst_file: Path) -> TestResult:
+        """Run test for a single RST file."""
+        with tempfile.TemporaryDirectory() as temp_dir:
+            temp_path = Path(temp_dir)
+            
+            # Create minimal conf.py
+            conf_file = temp_path / "conf.py"
+            conf_content = """
+project = 'Test'
+extensions = ['sphinx.ext.needs']
+html_theme = 'basic'
+"""
+            conf_file.write_text(conf_content)
+            
+            # Copy RST file
+            rst_dest = temp_path / rst_file.name
+            shutil.copy2(rst_file, rst_dest)
+            
+            # Build
+            build_path = temp_path / "_build"
+            return self._build_sphinx_project(temp_path, build_path)
+    
+    def run_multifile_test(self, testcase_dir: Path) -> TestResult:
+        """Run test for a multi-file testcase directory."""
+        with tempfile.TemporaryDirectory() as temp_dir:
+            temp_path = Path(temp_dir)
+            
+            # Create minimal conf.py in the testcase directory
+            conf_file = testcase_dir / "conf.py"
+            if not conf_file.exists():
+                conf_content = """
+project = 'Test'
+extensions = ['sphinx.ext.needs']
+html_theme = 'basic'
+"""
+                conf_file.write_text(conf_content)
+            
+            # Copy entire directory
+            dest_dir = temp_path / testcase_dir.name
+            shutil.copytree(testcase_dir, dest_dir)
+            
+            # Build
+            build_path = temp_path / "_build"
+            result = self._build_sphinx_project(dest_dir, build_path)
+            
+            # For multi-file tests, filter warnings to only include files in the testcase
+            filtered_warnings = [
+                w for w in result.warnings 
+                if w[0] in [f.name for f in testcase_dir.glob("*.rst")] or w[0] == "index.rst"
+            ]
+            
+            return TestResult(
+                success=result.success,
+                warnings=filtered_warnings,
+                error=result.error
+            )
+    
+    def run_test(self, testcase_path: str) -> TestResult:
+        """
+        Run an RST test case.
+        
+        Args:
+            testcase_path: Path to either a single .rst file or a directory containing
+                          an index.rst and related files.
+        
+        Returns:
+            TestResult with success status and any warnings.
+        """
+        path = Path(testcase_path)
+        
+        if not path.exists():
+            return TestResult(
+                success=False,
+                warnings=[],
+                error=f"Test case not found: {testcase_path}"
+            )
+        
+        if path.is_dir():
+            if not self._is_mult