test: Add comprehensive tests for address validation utilities and ensure secure binding addresses (127.0.0.1) are used instead of wildcard (0.0.0.0)

tests/examples/test_examples_bind_address.py

@@ -0,0 +1,110 @@
+"""
+Tests to verify that all examples use 127.0.0.1 instead of 0.0.0.0
+"""
+
+import ast
+import os
+from pathlib import Path
+
+
+class TestExamplesBindAddress:
+    """Test suite to verify all examples use secure bind addresses"""
+
+    def get_example_files(self):
+        """Get all Python files in the examples directory"""
+        examples_dir = Path("examples")
+        return list(examples_dir.rglob("*.py"))
+
+    def check_file_for_wildcard_binding(self, filepath):
+        """Check if a file contains 0.0.0.0 binding"""
+        with open(filepath, 'r', encoding='utf-8') as f:
+            content = f.read()
+        
+        # Check for various forms of wildcard binding
+        wildcard_patterns = [
+            '0.0.0.0',
+            '/ip4/0.0.0.0/',
+        ]
+        
+        found_wildcards = []
+        for line_num, line in enumerate(content.splitlines(), 1):
+            for pattern in wildcard_patterns:
+                if pattern in line and not line.strip().startswith('#'):
+                    found_wildcards.append((line_num, line.strip()))
+        
+        return found_wildcards
+
+    def test_no_wildcard_binding_in_examples(self):
+        """Test that no example files use 0.0.0.0 for binding"""
+        example_files = self.get_example_files()
+        
+        # Skip certain files that might legitimately discuss wildcards
+        skip_files = [
+            'network_discover.py',  # This demonstrates wildcard expansion
+        ]
+        
+        files_with_wildcards = {}
+        
+        for filepath in example_files:
+            if any(skip in str(filepath) for skip in skip_files):
+                continue
+                
+            wildcards = self.check_file_for_wildcard_binding(filepath)
+            if wildcards:
+                files_with_wildcards[str(filepath)] = wildcards
+        
+        # Assert no wildcards found
+        if files_with_wildcards:
+            error_msg = "Found wildcard bindings in example files:\n"
+            for filepath, occurrences in files_with_wildcards.items():
+                error_msg += f"\n{filepath}:\n"
+                for line_num, line in occurrences:
+                    error_msg += f"  Line {line_num}: {line}\n"
+            
+            assert False, error_msg
+
+    def test_examples_use_loopback_address(self):
+        """Test that examples use 127.0.0.1 for local binding"""
+        example_files = self.get_example_files()
+        
+        # Files that should contain listen addresses
+        files_with_networking = [
+            'ping/ping.py',
+            'chat/chat.py',
+            'bootstrap/bootstrap.py',
+            'pubsub/pubsub.py',
+            'identify/identify.py',
+        ]
+        
+        for filename in files_with_networking:
+            filepath = None
+            for example_file in example_files:
+                if filename in str(example_file):
+                    filepath = example_file
+                    break
+            
+            if filepath is None:
+                continue
+                
+            with open(filepath, 'r', encoding='utf-8') as f:
+                content = f.read()
+            
+            # Check for proper loopback usage
+            has_loopback = '127.0.0.1' in content or 'localhost' in content
+            has_multiaddr_loopback = '/ip4/127.0.0.1/' in content
+            
+            assert has_loopback or has_multiaddr_loopback, \
+                f"{filepath} should use loopback address (127.0.0.1)"
+
+    def test_doc_examples_use_loopback(self):
+        """Test that documentation examples use secure addresses"""
+        doc_examples_dir = Path("examples/doc-examples")
+        if not doc_examples_dir.exists():
+            return
+            
+        doc_example_files = list(doc_examples_dir.glob("*.py"))
+        
+        for filepath in doc_example_files:
+            wildcards = self.check_file_for_wildcard_binding(filepath)
+            assert not wildcards, \
+                f"Documentation example {filepath} contains wildcard binding"