idna: add test for domains containing non-ASCII dots

Change-Id: I1011371968c2a548378c7490212a39989a9de75e
Reviewed-on: https://go-review.googlesource.com/38284
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

idna/idna_test.go

@@ -39,5 +39,70 @@ func TestIDNA(t *testing.T) {
 	}
 }
 
+func TestIDNASeparators(t *testing.T) {
+	type subCase struct {
+		unicode   string
+		wantASCII string
+		wantErr   bool
+	}
+
+	testCases := []struct {
+		name     string
+		profile  *Profile
+		subCases []subCase
+	}{
+		{
+			name: "Punycode", profile: Punycode,
+			subCases: []subCase{
+				{"example\u3002jp", "xn--examplejp-ck3h", false},
+				{"東京\uFF0Ejp", "xn--jp-l92cn98g071o", false},
+				{"大阪\uFF61jp", "xn--jp-ku9cz72u463f", false},
+			},
+		},
+		{
+			name: "Lookup", profile: Lookup,
+			subCases: []subCase{
+				{"example\u3002jp", "example.jp", false},
+				{"東京\uFF0Ejp", "xn--1lqs71d.jp", false},
+				{"大阪\uFF61jp", "xn--pssu33l.jp", false},
+			},
+		},
+		{
+			name: "Display", profile: Display,
+			subCases: []subCase{
+				{"example\u3002jp", "example.jp", false},
+				{"東京\uFF0Ejp", "xn--1lqs71d.jp", false},
+				{"大阪\uFF61jp", "xn--pssu33l.jp", false},
+			},
+		},
+		{
+			name: "Registration", profile: Registration,
+			subCases: []subCase{
+				{"example\u3002jp", "", true},
+				{"東京\uFF0Ejp", "", true},
+				{"大阪\uFF61jp", "", true},
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			for _, c := range tc.subCases {
+				gotA, err := tc.profile.ToASCII(c.unicode)
+				if c.wantErr {
+					if err == nil {
+						t.Errorf("ToASCII(%q): got no error, but an error expected", c.unicode)
+					}
+				} else {
+					if err != nil {
+						t.Errorf("ToASCII(%q): got err=%v, but no error expected", c.unicode, err)
+					} else if gotA != c.wantASCII {
+						t.Errorf("ToASCII(%q): got %q, want %q", c.unicode, gotA, c.wantASCII)
+					}
+				}
+			}
+		})
+	}
+}
+
 // TODO(nigeltao): test errors, once we've specified when ToASCII and ToUnicode
 // return errors.