test: add a module interface test

Author: nkcsgexi

test/ModuleInterface/spi-available.swift

@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -parse-as-library %s -emit-module -library-level=api -emit-module-path %t/Foo.swiftmodule -module-name Foo -emit-module-interface-path %t/Foo.swiftinterface -emit-private-module-interface-path %t/Foo.private.swiftinterface
+
+// RUN: %target-swift-frontend -compile-module-from-interface %t/Foo.swiftinterface -o %t/Foo.public.swiftmodule -module-name Foo
+// RUN: %target-swift-frontend -compile-module-from-interface %t/Foo.private.swiftinterface -o %t/Foo.private.swiftmodule -module-name Foo
+
+@_spi_available(macOS 10.10, *)
+@available(iOS 8.0, *)
+public class SPIClass {}
+
+// RUN: %FileCheck %s -check-prefix CHECK-PUBLIC < %t/Foo.swiftinterface
+// RUN: %FileCheck %s -check-prefix CHECK-PRIVATE < %t/Foo.private.swiftinterface
+
+// CHECK-PUBLIC: @available(macOS, unavailable)
+// CHECK-PRIVATE: @_spi_available(macOS, introduced: 10.10)