test: harden codex analyzer coverage

tests/test_codex_analyzer.py

@@ -25,6 +25,17 @@ def fake_runner(stdout: str):
     return runner
 
 
+def fake_which(path: str = "/tmp/fake-codex"):
+    calls: list[str] = []
+
+    def which(name: str) -> str:
+        calls.append(name)
+        return path
+
+    which.calls = calls
+    return which
+
+
 def missing_which(name: str) -> None:
     assert name == "codex"
     return None
@@ -37,26 +48,39 @@ def test_analyzer_fails_when_codex_is_missing():
 
 def test_analyzer_rejects_non_json_output():
     runner = fake_runner(stdout="not json")
+    which = fake_which()
 
     with pytest.raises(ValueError):
-        analyze_with_codex(candles=sample_candles(), symbol="BTC-USDT-SWAP", bar="1H", runner=runner)
+        analyze_with_codex(candles=sample_candles(), symbol="BTC-USDT-SWAP", bar="1H", runner=runner, which=which)
+
+    assert which.calls == ["codex"]
 
 
 def test_analyzer_rejects_json_leverage_out_of_range():
     runner = fake_runner(
         stdout='{"action":"long","confidence":0.8,"leverage":4,"entry_price":null,"take_profit_price":null,"stop_loss_price":null,"reason":"x"}'
     )
+    which = fake_which()
 
     with pytest.raises(ValueError):
-        analyze_with_codex(candles=sample_candles(), symbol="BTC-USDT-SWAP", bar="1H", runner=runner)
+        analyze_with_codex(candles=sample_candles(), symbol="BTC-USDT-SWAP", bar="1H", runner=runner, which=which)
+
+    assert which.calls == ["codex"]
 
 
 def test_analyzer_returns_valid_trade_signal():
     runner = fake_runner(
         stdout='{"action":"short","confidence":0.6,"leverage":2,"entry_price":101.5,"take_profit_price":99.0,"stop_loss_price":103.0,"reason":"trend"}'
     )
-
-    signal = analyze_with_codex(candles=sample_candles(), symbol="BTC-USDT-SWAP", bar="1H", runner=runner)
+    which = fake_which()
+
+    signal = analyze_with_codex(
+        candles=sample_candles(),
+        symbol="BTC-USDT-SWAP",
+        bar="1H",
+        runner=runner,
+        which=which,
+    )
 
     assert signal.action == "short"
     assert signal.confidence == 0.6
@@ -65,6 +89,13 @@ def test_analyzer_returns_valid_trade_signal():
     assert signal.take_profit_price == 99.0
     assert signal.stop_loss_price == 103.0
     assert signal.reason == "trend"
+    assert which.calls == ["codex"]
     assert runner.calls
     assert runner.calls[0][0][0:2] == ["codex", "exec"]
     assert runner.calls[0][1:] == (True, True, False)
+    prompt = runner.calls[0][0][2]
+    assert "return exactly one JSON object" in prompt
+    assert "Do not output markdown, prose, or code fences." in prompt
+    assert '"action", "confidence", "leverage", "entry_price", "take_profit_price", "stop_loss_price", "reason"' in prompt
+    assert 'Valid actions are "long", "short", and "flat".' in prompt
+    assert 'candles: [{"symbol":"BTC-USDT-SWAP"' in prompt