DNSimpleProvider: Check valid credentials

acme/dns_challenge_dnsimple.go

@@ -1,6 +1,8 @@
 package acme
 
 import (
+	"fmt"
+
 	"github.com/weppos/go-dnsimple/dnsimple"
 )
 
@@ -12,7 +14,15 @@ type DNSProviderDNSimple struct {
 // NewDNSProviderDNSimple returns a DNSProviderDNSimple instance with a configured dnsimple client.
 // Authentication is either done using the passed credentials.
 func NewDNSProviderDNSimple(dnsimpleEmail, dnsimpleApiKey string) (*DNSProviderDNSimple, error) {
-	return nil, nil
+	if dnsimpleEmail == "" || dnsimpleApiKey == "" {
+		return nil, fmt.Errorf("DNSimple credentials missing")
+	}
+
+	c := &DNSProviderDNSimple{
+		client: dnsimple.NewClient(dnsimpleApiKey, dnsimpleEmail),
+	}
+
+	return c, nil
 }
 
 // Present creates a TXT record to fulfil the dns-01 challenge.

acme/dns_challenge_dnsimple_test.go

@@ -6,8 +6,12 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-
 func TestNewDNSProviderDNSimpleValid(t *testing.T) {
 	_, err := NewDNSProviderDNSimple("example@example.com", "123")
 	assert.NoError(t, err)
 }
+
+func TestNewDNSProviderDNSimpleMissingCredErr(t *testing.T) {
+	_, err := NewDNSProviderDNSimple("", "")
+	assert.EqualError(t, err, "DNSimple credentials missing")
+}