Refactor: use SecretStr for StochasticAI llms (#15118)

libs/community/tests/unit_tests/llms/test_stochasticai.py

@@ -0,0 +1,19 @@
+from langchain_core.pydantic_v1 import SecretStr
+from pytest import CaptureFixture
+
+from langchain_community.llms.stochasticai import StochasticAI
+
+
+def test_api_key_is_string() -> None:
+    llm = StochasticAI(stochasticai_api_key="secret-api-key")
+    assert isinstance(llm.stochasticai_api_key, SecretStr)
+
+
+def test_api_key_masked_when_passed_via_constructor(
+    capsys: CaptureFixture,
+) -> None:
+    llm = StochasticAI(stochasticai_api_key="secret-api-key")
+    print(llm.stochasticai_api_key, end="")
+    captured = capsys.readouterr()
+
+    assert captured.out == "**********"