feat: parse provider definitions from config

Providers come from a [providers.*] table. A bare top-level base_url
synthesizes the local provider so existing configs keep working, and an
explicit [providers.local] wins over it. Unset numbers stay None so
'unknown' never collapses into zero.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/test_llamachat.py b/test_llamachat.py
index a06d737..6a5c0e6 100755
--- a/test_llamachat.py
+++ b/test_llamachat.py
@@ -905,6 +905,62 @@ def test_config_defaults():
     print("ok  config defaults")
 
 
+def test_provider_parsing():
+    """Providers come from [providers.*]; a bare base_url synthesizes local."""
+    from llamachat import providers
+
+    # A modern config with two providers.
+    parsed = providers.parse(
+        {
+            "providers": {
+                "local": {"base_url": "http://localhost:8181/"},
+                "together": {
+                    "base_url": "https://api.example.org",
+                    "api_key": "env:TEST_KEY_NAME",
+                    "filter": ["qwen", "deepseek"],
+                    "ctx_size": 32768,
+                    "price_in": 0.6,
+                    "price_out": 0.9,
+                },
+            }
+        }
+    )
+    assert set(parsed) == {"local", "together"}
+    # Trailing slashes are stripped so URL joining stays predictable.
+    assert parsed["local"].base_url == "http://localhost:8181"
+    assert parsed["local"].api_key == ""
+    assert parsed["together"].filter == ["qwen", "deepseek"]
+    assert parsed["together"].ctx_size == 32768
+    assert parsed["together"].price_in == 0.6
+    assert parsed["together"].price_out == 0.9
+
+    # An old config: bare base_url, no providers table at all.
+    legacy = providers.parse({"base_url": "http://localhost:8181"})
+    assert set(legacy) == {"local"}
+    assert legacy["local"].base_url == "http://localhost:8181"
+
+    # Both present: the explicit entry wins over the bare key.
+    both = providers.parse(
+        {
+            "base_url": "http://ignored.example.org",
+            "providers": {"local": {"base_url": "http://explicit.example.org"}},
+        }
+    )
+    assert both["local"].base_url == "http://explicit.example.org"
+
+    # A provider with no base_url is skipped rather than half-configured.
+    broken = providers.parse(
+        {"providers": {"local": {"base_url": "http://x.example.org"},
+                       "bad": {"api_key": "literal"}}}
+    )
+    assert set(broken) == {"local"}
+
+    # Unset numbers stay None so "unknown" is distinguishable from zero.
+    assert parsed["local"].ctx_size is None
+    assert parsed["local"].price_in is None
+    print("ok  provider config parsing")
+
+
 class _FakeResponse:
     """Enough of an http.client response for urlopen's context manager."""
 
@@ -1642,6 +1698,7 @@ if __name__ == "__main__":
     test_version_matches_changelog()
     test_venv_discovery()
     test_config_defaults()
+    test_provider_parsing()
     test_search_tool_schema()
     test_search_results_sanitising()
     test_tool_call_accumulation()