Suppress non-useful NaN test in llsd_new_tut.cpp

1 files changed, 12 insertions, 2 deletions

diff --git a/indra/test/llsd_new_tut.cpp b/indra/test/llsd_new_tut.cpp
index e1de1bbd34..81db191ca6 100755
--- a/indra/test/llsd_new_tut.cpp
+++ b/indra/test/llsd_new_tut.cpp
@@ -277,8 +277,18 @@ namespace tut
 		v = 0.5;		checkConversions("point5", v, true, 0, 0.5, "0.5");
 		v = 0.9;		checkConversions("point9", v, true, 0, 0.9, "0.9");
 		v = -3.9;		checkConversions("neg3dot9", v, true, -3, -3.9, "-3.9");
-		v = sqrt(-1.0);	checkConversions("NaN", v, false, 0, sqrt(-1.0), "nan");
-		
+		// Get rid of NaN test. First, some libraries don't reliably return
+		// NaN for sqrt(-1.0) -- meaning that I don't even know how to
+		// portably, reliably produce a NaN value. Second, we observe failures
+		// on different platforms in the asString() test. But LLSD's
+		// ImplReal::asString() does not itself recognize NaN! It merely
+		// passes the value through to llformat(), which passes it through to
+		// the library vsnprintf(). That is, even when we do produce NaN,
+		// we're not testing any LLSD code: we're testing the local library's
+		// vsnprintf() function, which (empirically) produces idiosyncratic
+		// results. This is just not a good test case.
+//		v = sqrt(-1.0);	checkConversions("NaN", v, false, 0, sqrt(-1.0), "nan");
+
 		v = "";			checkConversions("empty", v, false, 0, 0.0, "");
 		v = "0";		checkConversions("digit0", v, true, 0, 0.0, "0");
 		v = "10";		checkConversions("digit10", v, true, 10, 10.0, "10");