diff --git a/helpers/helpers_test.go b/helpers/helpers_test.go
new file mode 100644
index 0000000..9654af9
--- /dev/null
+++ b/helpers/helpers_test.go
@@ -0,0 +1,209 @@
+package helpers_test
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/blueprintue/discord-bot/helpers"
+	"github.com/bwmarrin/discordgo"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type mockRoundTripper struct {
+	idxResponse     int
+	test            *testing.T
+	responsesMocked []*http.Response
+	requestsTest    []requestTest
+}
+
+type requestTest struct {
+	method string
+	host   string
+	uri    string
+}
+
+func (r requestTest) assert(t *testing.T, req *http.Request) {
+	t.Helper()
+
+	assert.Equal(t, r.method, req.Method)
+	assert.Equal(t, r.host, req.Host)
+	assert.Equal(t, r.uri, req.URL.RequestURI())
+}
+
+func (rt *mockRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	rt.requestsTest[rt.idxResponse].assert(rt.test, req)
+
+	resp := rt.responsesMocked[rt.idxResponse]
+
+	rt.idxResponse++
+
+	return resp, nil
+}
+
+func TestMessageReactionsAll(t *testing.T) {
+	t.Parallel()
+
+	session, err := discordgo.New("fake-token")
+	require.NoError(t, err)
+
+	expectedUsers := []*discordgo.User{
+		{ID: "111"},
+		{ID: "222"},
+		{ID: "333"},
+	}
+
+	channelID := "channel-id"
+	messageID := "message-id"
+	emojiID := ":emoji:"
+
+	// user 111 + user 222
+	data1, err := json.Marshal(expectedUsers[:2])
+	require.NoError(t, err)
+
+	recorder1 := httptest.NewRecorder()
+	recorder1.Header().Add("Content-Type", "application/json")
+	_, err = recorder1.Write(data1)
+	require.NoError(t, err)
+
+	expectedResponse1 := recorder1.Result()
+	defer expectedResponse1.Body.Close()
+
+	// user 333
+	data2, err := json.Marshal(expectedUsers[2:])
+	require.NoError(t, err)
+
+	recorder2 := httptest.NewRecorder()
+	recorder2.Header().Add("Content-Type", "application/json")
+	_, err = recorder2.Write(data2)
+	require.NoError(t, err)
+
+	expectedResponse2 := recorder2.Result()
+	defer expectedResponse2.Body.Close()
+
+	// no user
+	recorder3 := httptest.NewRecorder()
+	recorder3.Header().Add("Content-Type", "application/json")
+	_, err = recorder3.WriteString("[]")
+	require.NoError(t, err)
+
+	expectedResponse3 := recorder3.Result()
+	defer expectedResponse3.Body.Close()
+
+	session.Client = createClient(t,
+		[]*http.Response{expectedResponse1, expectedResponse2, expectedResponse3},
+		[]requestTest{
+			{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?limit=100"},
+			{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?after=222&limit=100"},
+			{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?after=333&limit=100"},
+		},
+	)
+
+	actualUsers, err := helpers.MessageReactionsAll(session, channelID, messageID, emojiID)
+	require.NoError(t, err)
+	require.Equal(t, expectedUsers, actualUsers)
+}
+
+//nolint:funlen,tparallel
+func TestMessageReactionsAllErrors(t *testing.T) {
+	t.Parallel()
+
+	session, err := discordgo.New("fake-token")
+	require.NoError(t, err)
+
+	users := []*discordgo.User{
+		{ID: "111"},
+		{ID: "222"},
+		{ID: "333"},
+	}
+
+	channelID := "channel-id"
+	messageID := "message-id"
+	emojiID := ":emoji:"
+
+	//nolint:paralleltest
+	t.Run("should return users and error because json unmarshal failed", func(t *testing.T) {
+		// user 111 + user 222
+		data1, err := json.Marshal(users[:2])
+		require.NoError(t, err)
+
+		recorder1 := httptest.NewRecorder()
+		recorder1.Header().Add("Content-Type", "application/json")
+		_, err = recorder1.Write(data1)
+		require.NoError(t, err)
+
+		expectedResponse1 := recorder1.Result()
+		defer expectedResponse1.Body.Close()
+
+		// invalid json
+		recorder2 := httptest.NewRecorder()
+		recorder2.Header().Add("Content-Type", "application/json")
+		_, err = recorder2.WriteString("-")
+		require.NoError(t, err)
+
+		expectedResponse2 := recorder2.Result()
+		defer expectedResponse2.Body.Close()
+
+		session.Client = createClient(t,
+			[]*http.Response{expectedResponse1, expectedResponse2},
+			[]requestTest{
+				{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?limit=100"},
+				{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?after=222&limit=100"},
+			},
+		)
+
+		actualUsers, err := helpers.MessageReactionsAll(session, channelID, messageID, emojiID)
+		require.ErrorIs(t, err, discordgo.ErrJSONUnmarshal)
+		require.Equal(t, users[:2], actualUsers)
+	})
+
+	//nolint:paralleltest,bodyclose
+	t.Run("should return users and error because request failed", func(t *testing.T) {
+		// user 111 + user 222
+		data1, err := json.Marshal(users[:2])
+		require.NoError(t, err)
+
+		recorder1 := httptest.NewRecorder()
+		recorder1.Header().Add("Content-Type", "application/json")
+		_, err = recorder1.Write(data1)
+		require.NoError(t, err)
+
+		expectedResponse1 := recorder1.Result()
+		defer expectedResponse1.Body.Close()
+
+		// request failed
+		recorder2 := httptest.NewRecorder()
+		recorder2.Result().Status = "500 Internal Server Error"
+		recorder2.Result().StatusCode = 500
+
+		expectedResponse2 := recorder2.Result()
+		defer expectedResponse2.Body.Close()
+
+		session.Client = createClient(t,
+			[]*http.Response{expectedResponse1, expectedResponse2},
+			[]requestTest{
+				{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?limit=100"},
+				{method: "GET", host: "discord.com", uri: "/api/v9/channels/channel-id/messages/message-id/reactions/:emoji:?after=222&limit=100"},
+			},
+		)
+
+		actualUsers, err := helpers.MessageReactionsAll(session, channelID, messageID, emojiID)
+		require.ErrorContains(t, err, "HTTP 500 Internal Server Error")
+		require.Equal(t, users[:2], actualUsers)
+	})
+}
+
+func createClient(t *testing.T, responses []*http.Response, requests []requestTest) *http.Client {
+	t.Helper()
+
+	return &http.Client{
+		Transport: &mockRoundTripper{
+			idxResponse:     0,
+			test:            t,
+			responsesMocked: responses,
+			requestsTest:    requests,
+		},
+	}
+}