1 files changed, 123 insertions, 0 deletions
diff --git a/src/pal/tests/palsuite/c_runtime/sqrt/test1/test1.cpp b/src/pal/tests/palsuite/c_runtime/sqrt/test1/test1.cpp
new file mode 100644
index 0000000000..62d2251d61
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+++ b/src/pal/tests/palsuite/c_runtime/sqrt/test1/test1.cpp
@@ -0,0 +1,123 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+/*=====================================================================
+**
+** Source:  test1.c
+**
+** Purpose:  Call the sqrt function on a positive value, a positive value
+** with a decimal and on the maxium possible double value.  
+**
+**
+**===================================================================*/
+
+#include <palsuite.h>
+
+// binary64 (double) has a machine epsilon of 2^-52 (approx. 2.22e-16). However, this 
+// is slightly too accurate when writing tests meant to run against libm implementations
+// for various platforms. 2^-50 (approx. 8.88e-16) seems to be as accurate as we can get.
+//
+// The tests themselves will take PAL_EPSILON and adjust it according to the expected result
+// so that the delta used for comparison will compare the most significant digits and ignore
+// any digits that are outside the double precision range (15-17 digits).
+
+// For example, a test with an expect result in the format of 0.xxxxxxxxxxxxxxxxx will use
+// PAL_EPSILON for the variance, while an expected result in the format of 0.0xxxxxxxxxxxxxxxxx
+// will use PAL_EPSILON / 10 and and expected result in the format of x.xxxxxxxxxxxxxxxx will
+// use PAL_EPSILON * 10.
+#define PAL_EPSILON 8.8817841970012523e-16
+
+#define PAL_NAN     sqrt(-1.0)
+#define PAL_POSINF -log(0.0)
+#define PAL_NEGINF  log(0.0)
+
+/**
+ * Helper test structure
+ */
+struct test
+{
+    double value;     /* value to test the function with */
+    double expected;  /* expected result */
+    double variance;  /* maximum delta between the expected and actual result */
+};
+
+/**
+ * validate
+ *
+ * test validation function
+ */
+void __cdecl validate(double value, double expected, double variance)
+{
+    double result = sqrt(value);
+
+    /*
+     * The test is valid when the difference between result
+     * and expected is less than or equal to variance
+     */
+    double delta = fabs(result - expected);
+
+    if (delta > variance)
+    {
+        Fail("sqrt(%g) returned %20.17g when it should have returned %20.17g",
+             value, result, expected);
+    }
+}
+
+/**
+ * validate
+ *
+ * test validation function for values returning NaN
+ */
+void __cdecl validate_isnan(double value)
+{
+    double result = sqrt(value);
+
+    if (!_isnan(result))
+    {
+        Fail("sqrt(%g) returned %20.17g when it should have returned %20.17g",
+             value, result, PAL_NAN);
+    }
+}
+
+int __cdecl main(int argc, char **argv)
+{
+    struct test tests[] = 
+    {
+        /* value                   expected                variance */
+        {  0.31830988618379067,    0.56418958354775629,    PAL_EPSILON },       // value:  1 / pi
+        {  0.43429448190325183,    0.65901022898226081,    PAL_EPSILON },       // value:  log10(e)
+        {  0.63661977236758134,    0.79788456080286536,    PAL_EPSILON },       // value:  2 / pi
+        {  0.69314718055994531,    0.83255461115769776,    PAL_EPSILON },       // value:  ln(2)
+        {  0.70710678118654752,    0.84089641525371454,    PAL_EPSILON },       // value:  1 / sqrt(2)
+        {  0.78539816339744831,    0.88622692545275801,    PAL_EPSILON },       // value:  pi / 4
+        {  1,                      1,                      PAL_EPSILON * 10 },
+        {  1.1283791670955126,     1.0622519320271969,     PAL_EPSILON * 10 },  // value:  2 / sqrt(pi)
+        {  1.4142135623730950,     1.1892071150027211,     PAL_EPSILON * 10 },  // value:  sqrt(2)
+        {  1.4426950408889634,     1.2011224087864498,     PAL_EPSILON * 10 },  // value:  log2(e)
+        {  1.5707963267948966,     1.2533141373155003,     PAL_EPSILON * 10 },  // value:  pi / 2
+        {  2.3025850929940457,     1.5174271293851464,     PAL_EPSILON * 10 },  // value:  ln(10)
+        {  2.7182818284590452,     1.6487212707001281,     PAL_EPSILON * 10 },  // value:  e
+        {  3.1415926535897932,     1.7724538509055160,     PAL_EPSILON * 10 },  // value:  pi
+    };
+
+    /* PAL initialization */
+    if (PAL_Initialize(argc, argv) != 0)
+    {
+        return FAIL;
+    }
+    
+    validate(-0.0, -0.0, PAL_EPSILON);
+    validate( 0.0,  0.0, PAL_EPSILON);
+
+    for (int i = 0; i < (sizeof(tests) / sizeof(struct test)); i++)
+    {
+        validate(tests[i].value, tests[i].expected, tests[i].variance);
+        validate_isnan(-tests[i].value);
+    }
+    
+    validate_isnan(PAL_NAN);
+
+    PAL_Terminate();
+    return PASS;
+}