iter: test bad responses

api_client_iter.go

@@ -17,72 +17,61 @@ type IterResult struct {
 	Next     string
 }
 
-func createPagingIterator(
+func getIterResult(
 	fetchPage func(from string) (*http.Response, error),
-) iter.Seq2[*IterResult, error] {
+	cursor string,
+) (*IterResult, error) {
+	response, err := fetchPage(cursor)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch next page: %w", err)
+	}
+
+	defer response.Body.Close()
+
+	body, err := io.ReadAll(response.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response: %w", err)
+	}
+
 	type ResponseWithNext struct {
 		Next string `json:"next"`
 	}
+	var responseWithNext ResponseWithNext
+	if err := json.Unmarshal(body, &responseWithNext); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal response: %w", err)
+	}
 
-	cursor := ""
+	response.Body = io.NopCloser(bytes.NewReader(body))
+
+	iterResult := &IterResult{
+		Response: response,
+		Next:     responseWithNext.Next,
+	}
+
+	return iterResult, nil
+}
 
+func createPagingIterator(
+	fetchPage func(from string) (*http.Response, error),
+) iter.Seq2[*IterResult, error] {
+	cursor := ""
 	return func(yield func(*IterResult, error) bool) {
 		for {
-			// Fire the request
-			response, err := fetchPage(cursor)
+			iterResult, err := getIterResult(
+				fetchPage,
+				cursor,
+			)
 			if err != nil {
 				yield(nil, err)
 				return
 			}
-
-			// Read the body
-			body, err := io.ReadAll(response.Body)
-			if err != nil {
-				yield(
-					nil,
-					fmt.Errorf("failed to read response: %w", err),
-				)
-				return
-			}
-
-			// Close the body
-			if err := response.Body.Close(); err != nil {
-				yield(
-					nil,
-					fmt.Errorf("failed to close http response: %w", err),
-				)
+			cursor = iterResult.Next
+			if !yield(iterResult, err) {
 				return
 			}
-
-			// Look for the next token
-			var responseWithNext ResponseWithNext
-			if err := json.Unmarshal(body, &responseWithNext); err != nil {
-				yield(
-					nil,
-					fmt.Errorf("failed to unmarshal response: %w", err),
-				)
+			if cursor == "" {
 				return
 			}
-
-			// Replace the body and return the response
-			response.Body = io.NopCloser(bytes.NewReader(body))
-			if !yield(
-				&IterResult{
-					Response: response,
-					Next:     responseWithNext.Next,
-				},
-				nil,
-			) {
-				return
-			}
-
-			// Was this the last page?
-			if responseWithNext.Next == "" {
-				return
-			}
-
-			// Set the cursor for next page
-			cursor = responseWithNext.Next
 		}
 	}
 }

api_client_iter_test.go

@@ -55,6 +55,33 @@ func TestIterGet(t *testing.T) {
 
 }
 
+func TestIterGetBadResponse(t *testing.T) {
+	ct := newClientTest(
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			assert.Equal(t, "/leaksdb/sources", r.URL.Path)
+			w.Write([]byte(`{"next": 11, "items": []}`))
+		}),
+	)
+	defer ct.Close()
+
+	lastPageIndex := 0
+
+	for result, err := range ct.apiClient.IterGet(
+		"/leaksdb/sources",
+		nil,
+	) {
+		lastPageIndex = lastPageIndex + 1
+		if lastPageIndex > 2 {
+			// We are going crazy here...
+			break
+		}
+		assert.ErrorContains(t, err, "failed to unmarshal", "Bad next token should trigger an error")
+		assert.Nil(t, result, "bad response should not contain a result")
+	}
+
+	assert.Equal(t, 1, lastPageIndex, "Didn't get the expected number of pages")
+}
+
 func TestIterPostJson(t *testing.T) {
 	ct := newClientTest(
 		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {