vultr: fix port parsing regression; add tests

vultr/resource_firewall_rule.go

@@ -173,6 +173,9 @@ func resourceFirewallRuleDelete(d *schema.ResourceData, meta interface{}) error
 }
 
 func splitFirewallRule(portRange string) (int, int, error) {
+	if len(portRange) == 0 {
+		return 0, 0, nil
+	}
 	ports := strings.Split(portRange, "-")
 	from, err := strconv.Atoi(strings.TrimSpace(ports[0]))
 	if err != nil {

vultr/resource_firewall_rule_test.go

@@ -0,0 +1,77 @@
+package vultr
+
+import (
+	"testing"
+)
+
+func TestSplitFirewallRule(t *testing.T) {
+	cases := []struct {
+		portRange string
+		from      int
+		to        int
+		err       bool
+	}{
+		{
+			portRange: "",
+			from:      0,
+			to:        0,
+			err:       false,
+		},
+		{
+			portRange: ":",
+			from:      0,
+			to:        0,
+			err:       true,
+		},
+		{
+			portRange: "-",
+			from:      0,
+			to:        0,
+			err:       true,
+		},
+		{
+			portRange: "22",
+			from:      22,
+			to:        22,
+			err:       false,
+		},
+		{
+			portRange: "foo",
+			from:      0,
+			to:        0,
+			err:       true,
+		},
+		{
+			portRange: "22:23",
+			from:      0,
+			to:        0,
+			err:       true,
+		},
+		{
+			portRange: "22 - 23",
+			from:      22,
+			to:        23,
+			err:       false,
+		},
+		{
+			portRange: "80-81",
+			from:      80,
+			to:        81,
+			err:       false,
+		},
+	}
+
+	for i, c := range cases {
+		from, to, err := splitFirewallRule(c.portRange)
+		if (err != nil) != c.err {
+			no := "no"
+			if c.err {
+				no = "an"
+			}
+			t.Errorf("test case %d: expected %s error, got %v", i, no, err)
+		}
+		if from != c.from || to != c.to {
+			t.Errorf("test case %d: expected range %d:%d, got %d:%d", i, c.from, c.to, from, to)
+		}
+	}
+}