Take an io.Reader and use local test data

ranges/ranges.go

@@ -3,9 +3,9 @@ package ranges
 import (
 	"encoding/json"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
-	"net/http"
 	"strconv"
 	"time"
 )
@@ -77,21 +77,15 @@ func (r *Ranges) LookupIPv6(ip net.IP) ([]PrefixIPv6, error) {
 }
 
 //New is a constructor for Ranges
-func New(client *http.Client) (*Ranges, error) {
+func New(r io.Reader) (*Ranges, error) {
 	var ranges Ranges
 
-	res, err := client.Get(url)
+	doc, err := ioutil.ReadAll(r)
 	if err != nil {
 		return nil, err
 	}
 
-	defer res.Body.Close()
-	body, err := ioutil.ReadAll(res.Body)
-	if err != nil {
-		return nil, err
-	}
-
-	err = json.Unmarshal(body, &ranges)
+	err = json.Unmarshal(doc, &ranges)
 	if err != nil {
 		return nil, err
 	}

ranges/ranges_test.go

@@ -2,26 +2,31 @@ package ranges
 
 import (
 	"net"
-	"net/http"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
 func TestRanges(t *testing.T) {
-	client := new(http.Client)
-	ranges, err := New(client)
+	doc, err := os.Open("../test/ip-ranges.json")
+	require.NoError(t, err)
+
+	ranges, err := New(doc)
 	require.NoError(t, err)
 
 	t.Run("has IPv4 prefixes", func(t *testing.T) {
+		t.Parallel()
 		require.NotZero(t, ranges.PrefixesIPv4, "should have 1 or more prefixes")
 	})
 
 	t.Run("has IPv6 prefixes", func(t *testing.T) {
+		t.Parallel()
 		require.NotZero(t, ranges.PrefixesIPv6, "should have 1 or more prefixes")
 	})
 
 	t.Run("returns a Prefix struct for an IPv4 address", func(t *testing.T) {
+		t.Parallel()
 		prefix := PrefixIPv4{
 			IPPrefix:           "52.94.76.0/22",
 			Region:             "us-west-2",