Litellm router code coverage 3 (#6274)

* refactor(router.py): move assistants api endpoints to using 1 pass-through factory function

Reduces code, increases testing coverage

* refactor(router.py): reduce _common_check_available_deployment function size

make code more maintainable - reduce possible errors

* test(router_code_coverage.py): include batch_utils + pattern matching in enforced 100% code coverage

Improves reliability

* fix(router.py): fix model id match model dump

tests/code_coverage_tests/router_enforce_line_length.py

@@ -0,0 +1,66 @@
+import ast
+import os
+
+MAX_FUNCTION_LINES = 100
+
+
+def get_function_line_counts(file_path):
+    """
+    Extracts all function names and their line counts from a given Python file.
+    """
+    with open(file_path, "r") as file:
+        tree = ast.parse(file.read())
+
+    function_line_counts = []
+
+    for node in tree.body:
+        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            # Top-level functions
+            line_count = node.end_lineno - node.lineno + 1
+            function_line_counts.append((node.name, line_count))
+        elif isinstance(node, ast.ClassDef):
+            # Functions inside classes
+            for class_node in node.body:
+                if isinstance(class_node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+                    line_count = class_node.end_lineno - class_node.lineno + 1
+                    function_line_counts.append((class_node.name, line_count))
+
+    return function_line_counts
+
+
+ignored_functions = [
+    "__init__",
+]
+
+
+def check_function_lengths(router_file):
+    """
+    Checks if any function in the specified file exceeds the maximum allowed length.
+    """
+    function_line_counts = get_function_line_counts(router_file)
+    long_functions = [
+        (name, count)
+        for name, count in function_line_counts
+        if count > MAX_FUNCTION_LINES and name not in ignored_functions
+    ]
+
+    if long_functions:
+        print("The following functions exceed the allowed line count:")
+        for name, count in long_functions:
+            print(f"- {name}: {count} lines")
+        raise Exception(
+            f"{len(long_functions)} functions in {router_file} exceed {MAX_FUNCTION_LINES} lines"
+        )
+    else:
+        print("All functions in the router file are within the allowed line limit.")
+
+
+def main():
+    # Update this path to point to the correct location of router.py
+    router_file = "../../litellm/router.py"  # LOCAL TESTING
+
+    check_function_lengths(router_file)
+
+
+if __name__ == "__main__":
+    main()