QtTestLib: handle float16 the same as double and float

In QCOMPARE, handle NaNs and infinities the way tests want them
handled, rather than by strict IEEE rules. In particular, if a test
expects NaN, this lets it treat that just like any other expected
value, despite NaN != NaN as float16 values. Likewise, format
infinities and NaNs specially in toString() so that they're reported
consistently.

Enable the qfloat16 tests that depend on this QCOMPARE() behavior.
Refise the testlib selftest's float test to test qfloat16 the same way
it tests float and double (and format the test the same way).

This is a follow-up to 37f617c405a.

Change-Id: I433256a09b1657e6725d68d07c5f80d805bf586a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 12 insertions, 18 deletions

diff --git a/tests/auto/testlib/selftests/float/tst_float.cpp b/tests/auto/testlib/selftests/float/tst_float.cpp
index 621dd1ccd9..cefd8a57c4 100644
--- a/tests/auto/testlib/selftests/float/tst_float.cpp
+++ b/tests/auto/testlib/selftests/float/tst_float.cpp
@@ -175,28 +175,22 @@ void tst_float::float16Comparisons_data() const
 {
     QTest::addColumn<qfloat16>("operandLeft");
     QTest::addColumn<qfloat16>("operandRight");
+    qfloat16 zero(0), one(1);
 
-    QTest::newRow("should SUCCEED 1")
-        << qfloat16(0)
-        << qfloat16(0);
-
-    QTest::newRow("should FAIL 1")
-        << qfloat16(1.000)
-        << qfloat16(3.000);
-
-    QTest::newRow("should FAIL 2")
-        << qfloat16(1.000e-4f)
-        << qfloat16(3.000e-4f);
+    QTest::newRow("should FAIL 1") << one << qfloat16(3);
+    QTest::newRow("should PASS 1") << zero << zero;
+    QTest::newRow("should FAIL 2") << qfloat16(1e-4f) << qfloat16(3e-4f);
 
     // QCOMPARE for qfloat16s uses qFuzzyCompare()
+    QTest::newRow("should PASS 2") << qfloat16(1001) << qfloat16(1002);
+    QTest::newRow("should FAIL 3") << qfloat16(98) << qfloat16(99);
+    // ... which gets a bit unreliable near to the type's bounds
+    QTest::newRow("should PASS 3") << qfloat16(6e-5f) + qfloat16(6e-7f) << qfloat16(6e-5f) + qfloat16(11e-7f);
+    QTest::newRow("should FAIL 4") << qfloat16(6e-5f) - qfloat16(7e-7f) << qfloat16(6e-5f) - qfloat16(13e-7f);
+    QTest::newRow("should PASS 4") << qfloat16(6e4) + qfloat16(700) << qfloat16(6e4) + qfloat16(1200);
+    QTest::newRow("should FAIL 5") << qfloat16(6e4) - qfloat16(600) << qfloat16(6e4) - qfloat16(1200);
 
-    QTest::newRow("should FAIL 3")
-        << qfloat16(98)
-        << qfloat16(99);
-
-    QTest::newRow("should SUCCEED 2")
-        << qfloat16(1001)
-        << qfloat16(1002);
+    nonFinite_data(zero, one);
 }
 
 void tst_float::compareFloatTests() const