[Bugfix] remove fallback in guided_json (int range, patterns) (#16725)

Signed-off-by: csy1204 <josang1204@gmail.com>
Co-authored-by: 조상연[플레이스 AI] <sang-yeon.cho@navercorp.com>

tests/entrypoints/llm/test_guided_generate.py

@@ -305,7 +305,7 @@ def test_disable_guided_decoding_fallback(sample_regex, llm):
     with pytest.raises(
             ValueError,
             match="xgrammar does not support advanced JSON schema features "
-            "like enums, patterns or numeric ranges."):
+            "like string length, item limits, or property bounds."):
         llm.generate(prompts="This should fail",
                      sampling_params=sampling_params,
                      use_tqdm=True)
@@ -386,6 +386,62 @@ def test_guided_json_completion_with_enum(llm, guided_decoding_backend: str):
         jsonschema.validate(instance=output_json, schema=json_schema)
 
 
+@pytest.mark.skip_global_cleanup
+@pytest.mark.parametrize("guided_decoding_backend", GUIDED_DECODING_BACKENDS)
+def test_guided_number_range_json_completion(llm,
+                                             guided_decoding_backend: str):
+    sample_output_schema = {
+        "type": "object",
+        "properties": {
+            "age": {
+                "type": "integer",
+                "minimum": 18,
+                "maximum": 99
+            },
+            "score": {
+                "type": "number",
+                "minimum": 0.0,
+                "maximum": 100.0
+            },
+            "zipcode": {
+                "type": "string",
+                "pattern": r"^\d{5}(-\d{4})?$"
+            },
+        },
+        "required": ["age", "score", "zipcode"],
+    }
+    sampling_params = SamplingParams(
+        temperature=1.0,
+        max_tokens=1000,
+        guided_decoding=GuidedDecodingParams(json=sample_output_schema,
+                                             backend=guided_decoding_backend),
+    )
+    outputs = llm.generate(
+        prompts=[
+            "Create a JSON object for a user with age, score, and zipcode."
+        ] * 2,
+        sampling_params=sampling_params,
+        use_tqdm=True,
+    )
+
+    assert outputs is not None
+
+    for output in outputs:
+        assert output is not None
+        assert isinstance(output, RequestOutput)
+        prompt = output.prompt
+
+        generated_text = output.outputs[0].text
+        assert generated_text is not None
+        print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")
+        output_json = json.loads(generated_text)
+        jsonschema.validate(instance=output_json, schema=sample_output_schema)
+        assert 18 <= output_json["age"] <= 99
+        assert 0.0 <= output_json["score"] <= 100.0
+        assert (re.fullmatch(r"^\d{5}(-\d{4})?$", output_json["zipcode"])
+                is not None)
+
+
 @pytest.mark.skip_global_cleanup
 def test_guidance_no_additional_properties(llm):
     schema = {