chore(protocol): improve IPv6 address. (#268)

* docs: improve documentation and configuration handling

- Clarify valid values for the IP protocol in usage messages for both main application and proxy settings

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* test: improve IPv6 command execution tests

- Add a new test function `TestCommandWithIPv6` to check command execution with an IPv6 address
- Initialize test variables and expected output for the IPv6 command test
- Set up a `Plugin` struct with IPv6 host, user, port, key path, script, and command timeout for testing
- Verify that `plugin.Exec()` returns `nil` (no error) in the IPv6 test
- Assert that the output of the command execution matches the expected output in the IPv6 test

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* test: enhance test suite and CI robustness

- Add support for IPv6 protocol in `TestCommandWithIPv6` test case in `plugin_test.go`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update2

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update3

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update4

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update5

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update5

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update5

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

---------

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

plugin_test.go

@@ -797,7 +797,8 @@ func TestPlugin_hostPort(t *testing.T) {
 			name: "different port",
 			fields: fields{
 				Config: Config{
-					Port: 22,
+					Port:     22,
+					Protocol: easyssh.PROTOCOL_TCP4,
 				},
 			},
 			args: args{
@@ -806,6 +807,20 @@ func TestPlugin_hostPort(t *testing.T) {
 			wantHost: "localhost",
 			wantPort: "443",
 		},
+		{
+			name: "ipv6",
+			fields: fields{
+				Config: Config{
+					Port:     22,
+					Protocol: easyssh.PROTOCOL_TCP6,
+				},
+			},
+			args: args{
+				h: "::1",
+			},
+			wantHost: "::1",
+			wantPort: "22",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -949,3 +964,34 @@ func TestSudoCommand(t *testing.T) {
 	assert.Nil(t, plugin.Exec())
 	assert.Equal(t, unindent(expected), unindent(buffer.String()))
 }
+
+// TODO: TestCommandWithIPv6 is not working on github actions.
+// func TestCommandWithIPv6(t *testing.T) {
+// 	var (
+// 		buffer   bytes.Buffer
+// 		expected = `
+// 			======CMD======
+// 			whoami
+// 			======END======
+// 			out: drone-scp
+// 		`
+// 	)
+
+// 	plugin := Plugin{
+// 		Config: Config{
+// 			Host:     []string{"::1"},
+// 			Username: "drone-scp",
+// 			Port:     22,
+// 			KeyPath:  "./tests/.ssh/id_rsa",
+// 			Script: []string{
+// 				"whoami",
+// 			},
+// 			Protocol:       easyssh.PROTOCOL_TCP6,
+// 			CommandTimeout: 10 * time.Second,
+// 		},
+// 		Writer: &buffer,
+// 	}
+
+// 	assert.Nil(t, plugin.Exec())
+// 	assert.Equal(t, unindent(expected), unindent(buffer.String()))
+// }