IPVanish support (#475)

- Fix #410 and #416

internal/updater/providers/ipvanish/string_test.go

@@ -0,0 +1,43 @@
+package ipvanish
+
+import (
+	"testing"
+
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Stringify(t *testing.T) {
+	t.Parallel()
+	testCases := map[string]struct {
+		servers []models.IpvanishServer
+		s       string
+	}{
+		"no server": {
+			s: `func IpvanishServers() []models.IpvanishServer {
+	return []models.IpvanishServer{
+	}
+}`,
+		},
+		"multiple servers": {
+			servers: []models.IpvanishServer{
+				{Country: "A"},
+				{Country: "B"},
+			},
+			s: `func IpvanishServers() []models.IpvanishServer {
+	return []models.IpvanishServer{
+		{Country: "A", City: "", Hostname: "", TCP: false, UDP: false, IPs: []net.IP{}},
+		{Country: "B", City: "", Hostname: "", TCP: false, UDP: false, IPs: []net.IP{}},
+	}
+}`,
+		},
+	}
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			s := Stringify(testCase.servers)
+			assert.Equal(t, testCase.s, s)
+		})
+	}
+}