import std.math: feqrel;
// TODO: Use verified test points.
// The values below are from Excel 2003.
assert(fabs(normalInvCDF(0.001) - (-3.09023230616779))< 0.00000000000005);
assert(fabs(normalInvCDF(1e-50) - (-14.9333375347885))< 0.00000000000005);
assert(feqrel(normalInvCDF(0.999L), -normalInvCDF(0.001L)) > real.mant_dig-6);

// Excel 2003 gets all the following values wrong!
assert(normalInvCDF(0.0) == -real.infinity);
assert(normalInvCDF(1.0) == real.infinity);
assert(normalInvCDF(0.5) == 0);
// (Excel 2003 returns norminv(p) = -30 for all p < 1e-200).
// The value tested here is the one the function returned in Jan 2006.
real unknown1 = normalInvCDF(1e-250L);
assert( fabs(unknown1 -(-33.79958617269L) ) < 0.00000005);