fix: allow custom provider to configure thinking style (#4429)

tests/providers/test_custom_thinking_style.py

@@ -0,0 +1,47 @@
+"""Tests for custom provider thinking_style config passthrough."""
+
+from __future__ import annotations
+
+from nanobot.config.schema import ProviderConfig, ProvidersConfig
+from nanobot.providers.registry import create_dynamic_spec
+
+
+class TestCustomProviderThinkingStyle:
+    """Verify that thinking_style flows from config to ProviderSpec."""
+
+    def test_default_thinking_style_is_empty(self) -> None:
+        cfg = ProviderConfig()
+        assert cfg.thinking_style == ""
+
+    def test_create_dynamic_spec_default(self) -> None:
+        spec = create_dynamic_spec("custom")
+        assert spec.thinking_style == ""
+
+    def test_create_dynamic_spec_with_thinking_type(self) -> None:
+        spec = create_dynamic_spec("custom", thinking_style="thinking_type")
+        assert spec.thinking_style == "thinking_type"
+
+    def test_create_dynamic_spec_with_enable_thinking(self) -> None:
+        spec = create_dynamic_spec("custom", thinking_style="enable_thinking")
+        assert spec.thinking_style == "enable_thinking"
+
+    def test_create_dynamic_spec_with_reasoning_split(self) -> None:
+        spec = create_dynamic_spec("custom", thinking_style="reasoning_split")
+        assert spec.thinking_style == "reasoning_split"
+
+    def test_provider_config_accepts_camel_case(self) -> None:
+        """Config JSON uses camelCase: thinkingStyle."""
+        cfg = ProviderConfig.model_validate({"thinkingStyle": "thinking_type"})
+        assert cfg.thinking_style == "thinking_type"
+
+    def test_providers_config_custom_has_thinking_style(self) -> None:
+        """Full providers config round-trip."""
+        data = {
+            "custom": {
+                "apiKey": "sk-test",
+                "apiBase": "https://example.com/v1",
+                "thinkingStyle": "enable_thinking",
+            }
+        }
+        pc = ProvidersConfig.model_validate(data)
+        assert pc.custom.thinking_style == "enable_thinking"