[libc++] Increase portability of xalloc test

ldionne · ldionne · commit e90085029c4b · 2019-03-01T00:51:54.000Z
Do not assume that xalloc() starts at 0, which is not specified by the Standard. Thanks to Andrey Maksimov for the patch. Differential Revision: https://reviews.llvm.org/D58299 llvm-svn: 355160
diff --git a/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/xalloc.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios.base/ios.base.storage/xalloc.pass.cpp
@@ -17,11 +17,9 @@
 
 int main(int, char**)
 {
-    assert(std::ios_base::xalloc() == 0);
-    assert(std::ios_base::xalloc() == 1);
-    assert(std::ios_base::xalloc() == 2);
-    assert(std::ios_base::xalloc() == 3);
-    assert(std::ios_base::xalloc() == 4);
+    int index = std::ios_base::xalloc();
+    for (int i = 0; i < 10000; ++i)
+        assert(std::ios_base::xalloc() == ++index);
 
   return 0;
 }

Original file line number	Diff line number	Diff line change
`@@ -17,11 +17,9 @@`
`17`	`17`
`18`	`18`	`int main(int, char**)`
`19`	`19`	`{`
`20`		`- assert(std::ios_base::xalloc() == 0);`
`21`		`- assert(std::ios_base::xalloc() == 1);`
`22`		`- assert(std::ios_base::xalloc() == 2);`
`23`		`- assert(std::ios_base::xalloc() == 3);`
`24`		`- assert(std::ios_base::xalloc() == 4);`
	`20`	`+ int index = std::ios_base::xalloc();`
	`21`	`+ for (int i = 0; i < 10000; ++i)`
	`22`	`+ assert(std::ios_base::xalloc() == ++index);`
`25`	`23`
`26`	`24`	`return 0;`
`27`	`25`	`}`