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>

plugin_test.go

@@ -949,3 +949,32 @@ func TestSudoCommand(t *testing.T) {
 	assert.Nil(t, plugin.Exec())
 	assert.Equal(t, unindent(expected), unindent(buffer.String()))
 }
+
+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",
+			},
+			CommandTimeout: 10 * time.Second,
+		},
+		Writer: &buffer,
+	}
+
+	assert.Nil(t, plugin.Exec())
+	assert.Equal(t, unindent(expected), unindent(buffer.String()))
+}