Differentiate blank constructor API key errors

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

hyperbrowser/client/base.py

@@ -26,9 +26,10 @@ def __init__(
             )
 
         if config is None:
+            api_key_from_constructor = api_key is not None
             resolved_api_key = (
                 api_key
-                if api_key is not None
+                if api_key_from_constructor
                 else os.environ.get("HYPERBROWSER_API_KEY")
             )
             if resolved_api_key is None:
@@ -38,6 +39,8 @@ def __init__(
             if not isinstance(resolved_api_key, str):
                 raise HyperbrowserError("api_key must be a string")
             if not resolved_api_key.strip():
+                if api_key_from_constructor:
+                    raise HyperbrowserError("api_key must not be empty")
                 raise HyperbrowserError(
                     "API key must be provided via `api_key` or HYPERBROWSER_API_KEY"
                 )

tests/test_client_api_key.py

@@ -62,3 +62,17 @@ def test_sync_client_rejects_non_string_api_key():
 def test_async_client_rejects_non_string_api_key():
     with pytest.raises(HyperbrowserError, match="api_key must be a string"):
         AsyncHyperbrowser(api_key=123)  # type: ignore[arg-type]
+
+
+def test_sync_client_rejects_blank_constructor_api_key(monkeypatch):
+    monkeypatch.setenv("HYPERBROWSER_API_KEY", "env-key")
+
+    with pytest.raises(HyperbrowserError, match="api_key must not be empty"):
+        Hyperbrowser(api_key="   ")
+
+
+def test_async_client_rejects_blank_constructor_api_key(monkeypatch):
+    monkeypatch.setenv("HYPERBROWSER_API_KEY", "env-key")
+
+    with pytest.raises(HyperbrowserError, match="api_key must not be empty"):
+        AsyncHyperbrowser(api_key="\t")