diff --git a/pkg/genericcli/prompt.go b/pkg/genericcli/prompt.go
index ed391d5..d739c32 100644
--- a/pkg/genericcli/prompt.go
+++ b/pkg/genericcli/prompt.go
@@ -51,6 +51,9 @@ func Prompt() error {
 
 // PromptCustomAnswers the user to given compare text
 func PromptCustom(c *PromptConfig) error {
+	if c == nil {
+		c = promptDefaultConfig()
+	}
 	if c.Message == "" {
 		c.Message = PromptDefaultQuestion()
 	}
diff --git a/pkg/genericcli/prompt_test.go b/pkg/genericcli/prompt_test.go
new file mode 100644
index 0000000..f031741
--- /dev/null
+++ b/pkg/genericcli/prompt_test.go
@@ -0,0 +1,80 @@
+package genericcli
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/metal-stack/metal-lib/pkg/testcommon"
+)
+
+func TestPromptCustom(t *testing.T) {
+	tests := []struct {
+		name    string
+		c       *PromptConfig
+		input   string
+		want    string
+		wantErr error
+	}{
+		{
+			name:  "default prompt config answered with yes",
+			input: "yes\n",
+			want:  "Do you want to continue? [y/n] ",
+		},
+		{
+			name:    "default prompt config answered with no",
+			input:   "no\n",
+			want:    "Do you want to continue? [y/n] ",
+			wantErr: fmt.Errorf(`aborting due to given answer ("no")`),
+		},
+		{
+			name:  "custom prompt config",
+			input: "ack\n",
+			c: &PromptConfig{
+				Message:         "Do you get it?",
+				ShowAnswers:     true,
+				AcceptedAnswers: []string{"ack", "a"},
+				DefaultAnswer:   "ack",
+				No:              "nack",
+			},
+			want: "Do you get it? [Ack/nack] ",
+		},
+		{
+			name:  "custom prompt config, default is no answer",
+			input: "ack\n",
+			c: &PromptConfig{
+				Message:         "Do you get it?",
+				ShowAnswers:     true,
+				AcceptedAnswers: []string{"ack", "a"},
+				DefaultAnswer:   "nack",
+				No:              "nack",
+			},
+			want: "Do you get it? [ack/Nack] ",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var (
+				in  bytes.Buffer
+				out bytes.Buffer
+			)
+
+			if tt.c == nil {
+				tt.c = promptDefaultConfig()
+			}
+			tt.c.In = &in
+			tt.c.Out = &out
+
+			in.WriteString(tt.input)
+
+			err := PromptCustom(tt.c)
+			if diff := cmp.Diff(tt.wantErr, err, testcommon.ErrorStringComparer()); diff != "" {
+				t.Errorf("error diff (+got -want):\n %s", diff)
+			}
+			if diff := cmp.Diff(tt.want, out.String()); diff != "" {
+				t.Errorf("diff (+got -want):\n %s", diff)
+			}
+		})
+	}
+}