RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt 2>&1 | %FileCheck -check-prefix NO-OUTPUT %s
NO-OUTPUT: argument -o is required

RUN: env -u SDKROOT SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -o %t 2>&1 | %FileCheck -check-prefix NO-SDK %s
NO-SDK: SDKROOT must be set

RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -o %t -sdk %S/nonexistent 2>&1 | %FileCheck -check-prefix BAD-SDK %s
BAD-SDK: invalid SDK: {{.+[/\\]nonexistent$}}