test: split provider detection tests (#4933)

tests/test_provider_detection_detect.py

@@ -0,0 +1,47 @@
+"""Provider detection tests — _detect_provider real hosts and false-positive rejection (re: #768).
+
+These import the *real* helpers from ``src.llm_core`` (not local copies) so a
+regression in hostname matching is actually caught. The point of the change
+under test is that provider detection keys off the URL's *hostname*, not a
+substring of the whole URL — so a domain appearing in a path/query, or a
+look-alike host, must not be misclassified.
+"""
+from src import llm_core
+
+
+class TestDetectProviderRealHosts:
+    def test_chatgpt_subscription_codex_backend(self):
+        assert llm_core._detect_provider("https://chatgpt.com/backend-api/codex") == "chatgpt-subscription"
+        assert llm_core._detect_provider("https://chatgpt.com/backend-api/codex/responses") == "chatgpt-subscription"
+
+    def test_anthropic(self):
+        assert llm_core._detect_provider("https://api.anthropic.com") == "anthropic"
+
+    def test_openrouter(self):
+        assert llm_core._detect_provider("https://openrouter.ai/api/v1") == "openrouter"
+
+    def test_groq_openai_compat_path(self):
+        # Groq's base carries an /openai/v1 path; detection must still see the host.
+        assert llm_core._detect_provider("https://api.groq.com/openai/v1") == "groq"
+
+    def test_ollama_native_unchanged(self):
+        assert llm_core._detect_provider("https://ollama.com/api") == "ollama"
+
+    def test_unknown_host_defaults_to_openai(self):
+        assert llm_core._detect_provider("https://api.example.com/v1") == "openai"
+
+
+class TestDetectProviderRejectsSubstringFalsePositives:
+    """The regression that motivated #768: substring matching mislabeled these."""
+
+    def test_provider_domain_in_path(self):
+        assert llm_core._detect_provider("https://myproxy.internal/anthropic.com/v1") == "openai"
+
+    def test_provider_domain_in_query(self):
+        assert llm_core._detect_provider("https://example.com/v1?ref=anthropic.com") == "openai"
+
+    def test_lookalike_host(self):
+        assert llm_core._detect_provider("https://anthropic.com.example/v1") == "openai"
+
+    def test_none_safe(self):
+        assert llm_core._detect_provider(None) == "openai"