Add tests

Signed-off-by: Maartje Eyskens <maartje@eyskens.me>

pkg/acme/util/util.go

@@ -31,7 +31,7 @@ func RetryBackoff(n int, r *http.Request, resp *http.Response) time.Duration {
 	// However, we can not use the request body in here as it is closed already.
 	// So we're using it's status code instead: 400
 	if resp.StatusCode == http.StatusBadRequest {
-		// don't retry more than 5 times, if we get 5 nonce mismatches something is quite wrong
+		// don't retry more than 6 times, if we get 6 nonce mismatches something is quite wrong
 		if n > 5 {
 			return -1
 		} else if n < 1 {

pkg/acme/util/util_test.go

@@ -0,0 +1,72 @@
+package util
+
+import (
+	"net/http"
+	"testing"
+	"time"
+)
+
+func TestRetryBackoff(t *testing.T) {
+	type args struct {
+		n    int
+		r    *http.Request
+		resp *http.Response
+	}
+	tests := []struct {
+		name            string
+		args            args
+		validdateOutput func(time.Duration) bool
+	}{
+		{
+			name: "Do not retry a non 400 error",
+			args: args{
+				n:    0,
+				r:    &http.Request{},
+				resp: &http.Response{StatusCode: http.StatusUnauthorized},
+			},
+			validdateOutput: func(duration time.Duration) bool {
+				return duration == -1
+			},
+		},
+		{
+			name: "Retry a 400 error when the first time",
+			args: args{
+				n:    0,
+				r:    &http.Request{},
+				resp: &http.Response{StatusCode: http.StatusBadRequest},
+			},
+			validdateOutput: func(duration time.Duration) bool {
+				return duration > 0
+			},
+		},
+		{
+			name: "Retry a 400 error when when less than 6 times",
+			args: args{
+				n:    5,
+				r:    &http.Request{},
+				resp: &http.Response{StatusCode: http.StatusBadRequest},
+			},
+			validdateOutput: func(duration time.Duration) bool {
+				return duration > 0
+			},
+		},
+		{
+			name: "Do not retry a 400 error after 6 tries",
+			args: args{
+				n:    6,
+				r:    &http.Request{},
+				resp: &http.Response{StatusCode: http.StatusBadRequest},
+			},
+			validdateOutput: func(duration time.Duration) bool {
+				return duration == -1
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := RetryBackoff(tt.args.n, tt.args.r, tt.args.resp); !tt.validdateOutput(got) {
+				t.Errorf("RetryBackoff() = %v which is not valid according to the validdateOutput()", got)
+			}
+		})
+	}
+}