fix rounding error. add tests to cover

Author: odow

REQUIRE

@@ -1,2 +1,2 @@
 julia 0.3-
-Compat
+Compat

src/fmtcore.jl

@@ -148,6 +148,11 @@ function _pfmt_float(out::IO, sch::Char, zs::Integer, intv::Real, decv::Real, pr
     if zs > 0
         _repwrite(out, '0', zs)
     end
+    idecv = round(Integer, decv * exp10(prec))
+    if idecv == exp10(prec)
+        intv += 1
+        idecv = 0
+    end
     # print integer part
     if intv == 0
         write(out, '0')
@@ -158,7 +163,6 @@ function _pfmt_float(out::IO, sch::Char, zs::Integer, intv::Real, decv::Real, pr
     write(out, '.')
     # print decimal part
     if prec > 0
-        idecv = round(Integer, decv * exp10(prec))
         nd = _ndigits(idecv, _Dec())
         if nd < prec
             _repwrite(out, '0', prec - nd)
@@ -201,6 +205,14 @@ end
 function _pfmt_floate(out::IO, sch::Char, zs::Integer, u::Real, prec::Int, e::Int, ec::Char)
     intv = trunc(Integer,u)
     decv = u - intv
+    if round(Integer, decv * exp10(prec)) == exp10(prec)
+        intv += 1
+        if intv == 10
+            intv = 1
+            e += 1
+        end
+        decv = 0.
+    end
     _pfmt_float(out, sch, zs, intv, decv, prec)
     write(out, ec)
     if e >= 0

test/fmtspec.jl

@@ -121,6 +121,12 @@ fs = FormatSpec("d")
 @test fmt("*<8.2f", -8.376) == "-8.38***"
 @test fmt("*>8.2f", -8.376) == "***-8.38"
 
+@test fmt(".2f", 0.999) == "1.00"
+@test fmt(".2f", 0.996) == "1.00"
+# Floating point error can upset this one (i.e. 0.99500000 or 0.994999999)
+@test (fmt(".2f", 0.995) == "1.00" || fmt(".2f", 0.995) == "0.99")
+@test fmt(".2f", 0.994) == "0.99"
+
 # format floating point (e)
 
 @test fmt("E", 0.0) == "0.000000E+00"
@@ -141,6 +147,14 @@ fs = FormatSpec("d")
 @test fmt("012.2e", -13.89) == "-0001.39e+01"
 @test fmt("+012.2e", 13.89) == "+0001.39e+01"
 
+@test fmt(".1e", 0.999) == "1.0e+00"
+@test fmt(".1e", 0.996) == "1.0e+00"
+# Floating point error can upset this one (i.e. 0.99500000 or 0.994999999)
+@test (fmt(".1e", 0.995) == "1.0e+00" || fmt(".1e", 0.995) == "9.9e-01")
+@test fmt(".1e", 0.994) == "9.9e-01"
+@test fmt(".1e", 0.6) == "6.0e-01"
+@test fmt(".1e", 0.9) == "9.0e-01"
+
 # format special floating point value
 
 @test fmt("f", NaN) == "NaN"