1 files changed, 85 insertions, 0 deletions
diff --git a/src/runtime/sqrt_test.go b/src/runtime/sqrt_test.go
new file mode 100644
index 0000000000..f1a6e8369d
--- /dev/null
+++ b/src/runtime/sqrt_test.go
@@ -0,0 +1,85 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// A copy of Sqrt tests from the math package to test the
+// purely integer arithmetic implementaiton in sqrt.go.
+
+package runtime_test
+
+import (
+	"math"
+	"runtime"
+	"testing"
+)
+
+func SqrtRT(x float64) float64 {
+	return math.Float64frombits(runtime.Sqrt(math.Float64bits(x)))
+}
+
+func TestSqrt(t *testing.T) {
+	for i := 0; i < len(vf); i++ {
+		a := math.Abs(vf[i])
+		if f := SqrtRT(a); sqrt[i] != f {
+			t.Errorf("Sqrt(%g) = %g, want %g", a, f, sqrt[i])
+		}
+	}
+	for i := 0; i < len(vfsqrtSC); i++ {
+		if f := SqrtRT(vfsqrtSC[i]); !alike(sqrtSC[i], f) {
+			t.Errorf("Sqrt(%g) = %g, want %g", vfsqrtSC[i], f, sqrtSC[i])
+		}
+	}
+}
+
+func alike(a, b float64) bool {
+	switch {
+	case math.IsNaN(a) && math.IsNaN(b):
+		return true
+	case a == b:
+		return math.Signbit(a) == math.Signbit(b)
+	}
+	return false
+}
+
+var vf = []float64{
+	4.9790119248836735e+00,
+	7.7388724745781045e+00,
+	-2.7688005719200159e-01,
+	-5.0106036182710749e+00,
+	9.6362937071984173e+00,
+	2.9263772392439646e+00,
+	5.2290834314593066e+00,
+	2.7279399104360102e+00,
+	1.8253080916808550e+00,
+	-8.6859247685756013e+00,
+}
+
+var sqrt = []float64{
+	2.2313699659365484748756904e+00,
+	2.7818829009464263511285458e+00,
+	5.2619393496314796848143251e-01,
+	2.2384377628763938724244104e+00,
+	3.1042380236055381099288487e+00,
+	1.7106657298385224403917771e+00,
+	2.286718922705479046148059e+00,
+	1.6516476350711159636222979e+00,
+	1.3510396336454586262419247e+00,
+	2.9471892997524949215723329e+00,
+}
+
+var vfsqrtSC = []float64{
+	math.Inf(-1),
+	-math.Pi,
+	math.Copysign(0, -1),
+	0,
+	math.Inf(1),
+	math.NaN(),
+}
+var sqrtSC = []float64{
+	math.NaN(),
+	math.NaN(),
+	math.Copysign(0, -1),
+	0,
+	math.Inf(1),
+	math.NaN(),
+}