diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index fd62e7c..11967c5 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -3,6 +3,12 @@ stages:
   - format
   - test
 
+check-generate:
+  stage: format
+  image: nixos/nix:latest
+  script:
+    - nix-shell --run "make generate && git diff --quiet"
+
 check-fmt:
   stage: format
   image: nixos/nix:latest
diff --git a/Makefile b/Makefile
index 7e4f452..428f401 100644
--- a/Makefile
+++ b/Makefile
@@ -13,3 +13,6 @@ fmt:
 
 run:
 	go run ./cmd/birthdaybot -config example-config.yml
+
+generate:
+	go generate ./...
diff --git a/go.mod b/go.mod
index e78b043..88e7870 100644
--- a/go.mod
+++ b/go.mod
@@ -5,6 +5,7 @@ go 1.20
 require (
 	github.com/charmbracelet/log v0.2.2
 	github.com/go-telegram-bot-api/telegram-bot-api/v5 v5.5.1
+	github.com/golang/mock v1.6.0
 	github.com/stretchr/testify v1.8.3
 	gopkg.in/yaml.v3 v3.0.1
 )
diff --git a/go.sum b/go.sum
index 69b7a3d..3ce01f6 100644
--- a/go.sum
+++ b/go.sum
@@ -10,6 +10,8 @@ github.com/go-logfmt/logfmt v0.6.0 h1:wGYYu3uicYdqXVgoYbvnkrPVXkuLM1p1ifugDMEdRi
 github.com/go-logfmt/logfmt v0.6.0/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
 github.com/go-telegram-bot-api/telegram-bot-api/v5 v5.5.1 h1:wG8n/XJQ07TmjbITcGiUaOtXxdrINDz1b0J1w0SzqDc=
 github.com/go-telegram-bot-api/telegram-bot-api/v5 v5.5.1/go.mod h1:A2S0CWkNylc2phvKXWBBdD3K0iGnDBGbzRpISP2zBl8=
+github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
+github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/mattn/go-isatty v0.0.18 h1:DOKFKCQ7FNG2L1rbrmstDN4QVRdS89Nkh85u68Uwp98=
@@ -28,8 +30,31 @@ github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/stretchr/testify v1.8.3 h1:RP3t2pwF7cMEbC1dqtB6poj3niw/9gnV4Cjg5oW5gtY=
 github.com/stretchr/testify v1.8.3/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
diff --git a/notification/service.go b/notification/service.go
index 6d8a157..4feadf5 100644
--- a/notification/service.go
+++ b/notification/service.go
@@ -1,3 +1,4 @@
+//go:generate mockgen -source=service.go -destination=service_mock.go -package=notification
 package notification
 
 import (
diff --git a/notification/service_mock.go b/notification/service_mock.go
new file mode 100644
index 0000000..42712f7
--- /dev/null
+++ b/notification/service_mock.go
@@ -0,0 +1,49 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: service.go
+
+// Package notification is a generated GoMock package.
+package notification
+
+import (
+	reflect "reflect"
+
+	model "git.ctrlz.es/mgdelacroix/birthdaybot/model"
+	gomock "github.com/golang/mock/gomock"
+)
+
+// MockNotificationService is a mock of NotificationService interface.
+type MockNotificationService struct {
+	ctrl     *gomock.Controller
+	recorder *MockNotificationServiceMockRecorder
+}
+
+// MockNotificationServiceMockRecorder is the mock recorder for MockNotificationService.
+type MockNotificationServiceMockRecorder struct {
+	mock *MockNotificationService
+}
+
+// NewMockNotificationService creates a new mock instance.
+func NewMockNotificationService(ctrl *gomock.Controller) *MockNotificationService {
+	mock := &MockNotificationService{ctrl: ctrl}
+	mock.recorder = &MockNotificationServiceMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockNotificationService) EXPECT() *MockNotificationServiceMockRecorder {
+	return m.recorder
+}
+
+// Notify mocks base method.
+func (m *MockNotificationService) Notify(arg0 *model.Birthday) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Notify", arg0)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// Notify indicates an expected call of Notify.
+func (mr *MockNotificationServiceMockRecorder) Notify(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Notify", reflect.TypeOf((*MockNotificationService)(nil).Notify), arg0)
+}
diff --git a/shell.nix b/shell.nix
index c612a45..dd84f05 100644
--- a/shell.nix
+++ b/shell.nix
@@ -14,6 +14,7 @@ pkgs.mkShell {
     gotestsum
     gnumake
     modd
+    mockgen
   ];
 
   shellHook = ''