bugfix for ProviderID parsing & corresponding unit test

pkg/cloudprovider/providers/aws/aws.go

@@ -3583,7 +3583,7 @@ var providerIDRegexp = regexp.MustCompile(`^aws://([^/]+)$`)
 
 func instanceIDFromProviderID(providerID string) (instanceID string, err error) {
 	matches := providerIDRegexp.FindStringSubmatch(providerID)
-	if len(matches) != 1 {
+	if len(matches) != 2 {
 		return "", fmt.Errorf("ProviderID \"%s\" didn't match expected format \"aws://InstanceID\"", providerID)
 	}
 

pkg/cloudprovider/providers/aws/aws_test.go

@@ -322,6 +322,12 @@ func (self *FakeEC2) DescribeInstances(request *ec2.DescribeInstancesInput) ([]*
 	return matches, nil
 }
 
+func (self *FakeEC2) DescribeAddresses(request *ec2.DescribeAddressesInput) ([]*ec2.Address, error) {
+	addresses := []*ec2.Address{}
+
+	return addresses, nil
+}
+
 type FakeMetadata struct {
 	aws *FakeAWSServices
 }
@@ -1350,3 +1356,37 @@ func TestGetLoadBalancerAdditionalTags(t *testing.T) {
 		}
 	}
 }
+
+func TestInstanceIDFromProviderID(t *testing.T) {
+	testCases := []struct {
+		providerID string
+		instanceID string
+		fail       bool
+	}{
+		{
+			providerID: "aws://i-0194bbdb81a49b169",
+			instanceID: "i-0194bbdb81a49b169",
+			fail:       false,
+		},
+		{
+			providerID: "i-0194bbdb81a49b169",
+			instanceID: "",
+			fail:       true,
+		},
+	}
+
+	for _, test := range testCases {
+		instanceID, err := instanceIDFromProviderID(test.providerID)
+		if (err != nil) != test.fail {
+			t.Errorf("%s yielded `err != nil` as %t. expected %t", test.providerID, (err != nil), test.fail)
+		}
+
+		if test.fail {
+			continue
+		}
+
+		if instanceID != test.instanceID {
+			t.Errorf("%s yielded %s. expected %s", test.providerID, instanceID, test.instanceID)
+		}
+	}
+}