Don't strip zeroes from numbers that don't have decimal points

Fixes #106

ftoa.go

@@ -6,6 +6,9 @@ import (
 )
 
 func stripTrailingZeros(s string) string {
+	if !strings.ContainsRune(s, '.') {
+		return s
+	}
 	offset := len(s) - 1
 	for offset > 0 {
 		if s[offset] == '.' {

ftoa_test.go

@@ -14,6 +14,7 @@ import (
 func TestFtoa(t *testing.T) {
 	testList{
 		{"200", Ftoa(200), "200"},
+		{"20", Ftoa(20.0), "20"},
 		{"2", Ftoa(2), "2"},
 		{"2.2", Ftoa(2.2), "2.2"},
 		{"2.02", Ftoa(2.02), "2.02"},
@@ -24,6 +25,7 @@ func TestFtoa(t *testing.T) {
 func TestFtoaWithDigits(t *testing.T) {
 	testList{
 		{"1.23, 0", FtoaWithDigits(1.23, 0), "1"},
+		{"20, 0", FtoaWithDigits(20.0, 0), "20"},
 		{"1.23, 1", FtoaWithDigits(1.23, 1), "1.2"},
 		{"1.23, 2", FtoaWithDigits(1.23, 2), "1.23"},
 		{"1.23, 3", FtoaWithDigits(1.23, 3), "1.23"},

si_test.go

@@ -126,3 +126,20 @@ func BenchmarkParseSI(b *testing.B) {
 		ParseSI("2.2346ZB")
 	}
 }
+
+// There was a report that zeroes were being truncated incorrectly
+func TestBug106(t *testing.T) {
+	tests := []struct{
+		in float64
+		want string
+	}{
+		{20.0, "20 U"},
+		{200.0, "200 U"},
+	}
+
+	for _, test := range tests {
+		if got :=SIWithDigits(test.in, 0, "U") ;  got != test.want {
+			t.Errorf("on %f got %v, want %v", test.in, got, test.want);
+		}
+	}
+}