[Test] Enhance radix cache test for spec cases (#12394)

python/sglang/test/kits/radix_cache_server_kit.py

@@ -0,0 +1,50 @@
+import random
+
+import requests
+
+
+def gen_radix_tree(num_nodes=400, chunk_len=256):
+    num0 = num_nodes // 2
+    num1 = num_nodes - num0
+    nodes = [{"input_ids": [37] * 117, "decode_len": 217}]
+    for _ in range(num0):
+        parent = random.choice(nodes)
+        unique_len = random.randint(0, chunk_len)
+        decode_len = random.randint(0, chunk_len)
+        token_id = random.randint(0, 32000)
+        child = {
+            "input_ids": parent["input_ids"] + [token_id] * unique_len,
+            "decode_len": decode_len,
+        }
+        nodes.append(child)
+
+    while num1 > 0:
+        num_branch = random.randint(1, min(num1, 10))
+        parent = random.choice(nodes)
+        for _ in range(num_branch):
+            unique_len = random.randint(0, chunk_len)
+            decode_len = random.randint(0, chunk_len)
+            token_id = random.randint(0, 32000)
+            child = {
+                "input_ids": parent["input_ids"] + [token_id] * unique_len,
+                "decode_len": decode_len,
+            }
+            nodes.append(child)
+
+        num1 -= num_branch
+
+    random.shuffle(nodes)
+    return nodes
+
+
+def run_radix_attention_test(base_url: str):
+    nodes = gen_radix_tree()
+    data = {
+        "input_ids": [node["input_ids"] for node in nodes],
+        "sampling_params": [
+            {"max_new_tokens": node["decode_len"], "temperature": 0} for node in nodes
+        ],
+    }
+
+    res = requests.post(base_url + "/generate", json=data)
+    assert res.status_code == 200