Match ListDNSRecords per_page value to the API's

As outlined in github.com//pull/1169,
when no pagination options are passed in to ListDNSRecords,
autopagination is performed. However, the current PerPage
value doesn't match that of the official API. This commit
makes both values match. A new test is also implemented that
more explicitly tests the auto pagination behaviour.

Signed-off-by: Artur Rodrigues <[email protected]>

dns.go

@@ -89,6 +89,9 @@ type DNSListResponse struct {
 	ResultInfo `json:"result_info"`
 }
 
+// listDNSRecordsDefaultPageSize represents the default per_page size of the API
+var listDNSRecordsDefaultPageSize int = 100
+
 // nontransitionalLookup implements the nontransitional processing as specified in
 // Unicode Technical Standard 46 with almost all checkings off to maximize user freedom.
 var nontransitionalLookup = idna.New(
@@ -152,7 +155,10 @@ func (api *API) CreateDNSRecord(ctx context.Context, rc *ResourceContainer, para
 	return recordResp, nil
 }
 
-// ListDNSRecords returns a slice of DNS records for the given zone identifier.
+// ListDNSRecords returns a slice of DNS records for the given zone
+// identifier. If params doesn't include any pagination (ResultInfo)
+// options, auto pagination is performed with the default page size
+// of 100 records per request.
 //
 // API reference: https://api.cloudflare.com/#dns-records-for-a-zone-list-dns-records
 func (api *API) ListDNSRecords(ctx context.Context, rc *ResourceContainer, params ListDNSRecordsParams) ([]DNSRecord, *ResultInfo, error) {
@@ -170,7 +176,7 @@ func (api *API) ListDNSRecords(ctx context.Context, rc *ResourceContainer, param
 	}
 
 	if params.PerPage < 1 {
-		params.PerPage = 50
+		params.PerPage = listDNSRecordsDefaultPageSize
 	}
 
 	if params.Page < 1 {

dns_test.go

@@ -153,7 +153,7 @@ func TestCreateDNSRecord(t *testing.T) {
 	assert.Equal(t, want, actual)
 }
 
-func TestDNSRecords(t *testing.T) {
+func TestListDNSRecords(t *testing.T) {
 	setup()
 	defer teardown()
 
@@ -242,7 +242,7 @@ func TestDNSRecords(t *testing.T) {
 	assert.Equal(t, want, actual)
 }
 
-func TestDNSRecordsSearch(t *testing.T) {
+func TestListDNSRecordsSearch(t *testing.T) {
 	setup()
 	defer teardown()
 
@@ -341,6 +341,39 @@ func TestDNSRecordsSearch(t *testing.T) {
 	assert.Equal(t, want, actual)
 }
 
+func TestListDNSRecordsPagination(t *testing.T) {
+	// change listDNSRecordsDefaultPageSize value  to 1 to force pagination
+	listDNSRecordsDefaultPageSize = 1
+
+	setup()
+	defer teardown()
+
+	var page1Called, page2Called bool
+	handler := func(w http.ResponseWriter, r *http.Request) {
+		page := r.URL.Query().Get("page")
+		w.Header().Set("content-type", "application/json")
+
+		var response string
+		switch page {
+		case "1":
+			response = loadFixture("dns", "list_page_1")
+			page1Called = true
+		case "2":
+			response = loadFixture("dns", "list_page_2")
+			page2Called = true
+		}
+		fmt.Fprint(w, response)
+	}
+
+	mux.HandleFunc("/zones/"+testZoneID+"/dns_records", handler)
+
+	actual, _, err := client.ListDNSRecords(context.Background(), ZoneIdentifier(testZoneID), ListDNSRecordsParams{})
+	require.NoError(t, err)
+	assert.True(t, page1Called)
+	assert.True(t, page2Called)
+	assert.Len(t, actual, 2)
+}
+
 func TestDNSRecord(t *testing.T) {
 	setup()
 	defer teardown()

testdata/fixtures/dns/list_page_1.json

@@ -0,0 +1,37 @@
+{
+    "success": true,
+    "errors": [],
+    "messages": [],
+    "result": [
+        {
+            "id": "372e67954025e0ba6aaa6d586b9e0b59",
+            "type": "A",
+            "name": "example.com",
+            "content": "198.51.100.4",
+            "proxiable": true,
+            "proxied": true,
+            "ttl": 120,
+            "locked": false,
+            "zone_id": "d56084adb405e0b7e32c52321bf07be6",
+            "zone_name": "example.com",
+            "created_on": "2014-01-01T05:20:00Z",
+            "modified_on": "2014-01-01T05:20:00Z",
+            "data": {},
+            "meta": {
+                "auto_added": true,
+                "source": "primary"
+            },
+            "tags": [
+                "tag1",
+                "tag2extended"
+            ]
+        }
+    ],
+    "result_info": {
+        "count": 1,
+        "page": 1,
+        "per_page": 1,
+        "total_count": 2,
+        "total_pages": 2
+    }
+}

testdata/fixtures/dns/list_page_2.json

@@ -0,0 +1,37 @@
+{
+    "success": true,
+    "errors": [],
+    "messages": [],
+    "result": [
+        {
+            "id": "372e67954025e0ba6aaa6d586b9e0b59",
+            "type": "A",
+            "name": "www.example.com",
+            "content": "198.51.100.4",
+            "proxiable": true,
+            "proxied": true,
+            "ttl": 120,
+            "locked": false,
+            "zone_id": "d56084adb405e0b7e32c52321bf07be6",
+            "zone_name": "example.com",
+            "created_on": "2014-01-01T05:20:00Z",
+            "modified_on": "2014-01-01T05:20:00Z",
+            "data": {},
+            "meta": {
+                "auto_added": true,
+                "source": "primary"
+            },
+            "tags": [
+                "tag1",
+                "tag2extended"
+            ]
+        }
+    ],
+    "result_info": {
+        "count": 1,
+        "page": 2,
+        "per_page": 1,
+        "total_count": 2,
+        "total_pages": 2
+    }
+}