[cxx-interop] Test: initialize std::span in C++ from Swift array

Author: susmonteiro

test/Interop/Cxx/stdlib/Inputs/std-span.h

@@ -50,6 +50,10 @@ inline Span initSpan() {
   return Span(a);
 }
 
+inline Span initSpan(int arr[], size_t size) {
+  return Span(arr, size);
+}
+
 inline struct SpanBox getStructSpanBox() { return {iarray, iarray, sarray, sarray}; }
 
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_SPAN_H

test/Interop/Cxx/stdlib/use-std-span.swift

@@ -176,6 +176,18 @@ StdSpanTestSuite.test("Init SpanOfInt") {
   expectFalse(cs.empty())
 }
 
+StdSpanTestSuite.test("Init SpanOfInt from Swift array") {
+  var arr: [Int32] = [1, 2, 3]
+  arr.withUnsafeMutableBufferPointer{ ubpointer in
+    let s = initSpan(ubpointer.baseAddress!, ubpointer.count)
+    expectEqual(s.size(), 3)
+    expectFalse(s.empty())
+    expectEqual(s[0], 1)
+    expectEqual(s[1], 2)
+    expectEqual(s[2], 3)
+  }
+}
+
 StdSpanTestSuite.test("Access static SpanOfInt") {
   expectEqual(icspan.size(), 3)
   expectFalse(icspan.empty())