Implement BytesHex type of argument (#115)

BytesHex is an []byte represented as HEX-string

--bytes=010203040506070809 states for []bytes{1,2,3,4,5,6,7,8,9}

1 files changed, 72 insertions, 0 deletions

diff --git a/bytes_test.go b/bytes_test.go
new file mode 100644
index 0000000..cc4a769
--- /dev/null
+++ b/bytes_test.go
@@ -0,0 +1,72 @@
+package pflag
+
+import (
+	"fmt"
+	"os"
+	"testing"
+)
+
+func setUpBytesHex(bytesHex *[]byte) *FlagSet {
+	f := NewFlagSet("test", ContinueOnError)
+	f.BytesHexVar(bytesHex, "bytes", []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0}, "Some bytes in HEX")
+	f.BytesHexVarP(bytesHex, "bytes2", "B", []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0}, "Some bytes in HEX")
+	return f
+}
+
+func TestBytesHex(t *testing.T) {
+	testCases := []struct {
+		input    string
+		success  bool
+		expected string
+	}{
+		/// Positive cases
+		{"", true, ""}, // Is empty string OK ?
+		{"01", true, "01"},
+		{"0101", true, "0101"},
+		{"1234567890abcdef", true, "1234567890ABCDEF"},
+		{"1234567890ABCDEF", true, "1234567890ABCDEF"},
+
+		// Negative cases
+		{"0", false, ""},   // Short string
+		{"000", false, ""}, /// Odd-length string
+		{"qq", false, ""},  /// non-hex character
+	}
+
+	devnull, _ := os.Open(os.DevNull)
+	os.Stderr = devnull
+
+	for i := range testCases {
+		var bytesHex []byte
+		f := setUpBytesHex(&bytesHex)
+
+		tc := &testCases[i]
+
+		// --bytes
+		args := []string{
+			fmt.Sprintf("--bytes=%s", tc.input),
+			fmt.Sprintf("-B  %s", tc.input),
+			fmt.Sprintf("--bytes2=%s", tc.input),
+		}
+
+		for _, arg := range args {
+			err := f.Parse([]string{arg})
+
+			if err != nil && tc.success == true {
+				t.Errorf("expected success, got %q", err)
+				continue
+			} else if err == nil && tc.success == false {
+				// bytesHex, err := f.GetBytesHex("bytes")
+				t.Errorf("expected failure while processing %q", tc.input)
+				continue
+			} else if tc.success {
+				bytesHex, err := f.GetBytesHex("bytes")
+				if err != nil {
+					t.Errorf("Got error trying to fetch the IP flag: %v", err)
+				}
+				if fmt.Sprintf("%X", bytesHex) != tc.expected {
+					t.Errorf("expected %q, got '%X'", tc.expected, bytesHex)
+				}
+			}
+		}
+	}
+}