diff --git a/README.md b/README.md
index 2e41c22..2fe6558 100644
--- a/README.md
+++ b/README.md
@@ -18,8 +18,8 @@ kubectl-persistent-logger -deployment mydeploymentname
 ## TODO
 
 - [ ] Implement for other relevant resource types (replica set, stateful set)
-- [ ] Pass other options back to logger backend (--previous, --container, etc)
-- [ ] Test coverage
+- [ ] Pass other options back to logger backend (--container, etc)
+- [x] Test coverage
 - [ ] Improve context handling
 - [ ] Remove/hide debug logging
 
diff --git a/go.mod b/go.mod
index 278acfa..cebb9c4 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module git.netflux.io/rob/kubectl-persistent-logger
 go 1.18
 
 require (
+	github.com/stretchr/testify v1.7.0
 	k8s.io/api v0.24.0
 	k8s.io/apimachinery v0.24.0
 	k8s.io/client-go v0.24.0
@@ -13,6 +14,7 @@ require (
 	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/emicklei/go-restful v2.9.5+incompatible // indirect
+	github.com/evanphx/json-patch v4.12.0+incompatible // indirect
 	github.com/go-logr/logr v1.2.0 // indirect
 	github.com/go-openapi/jsonpointer v0.19.5 // indirect
 	github.com/go-openapi/jsonreference v0.19.5 // indirect
@@ -28,6 +30,8 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd // indirect
 	golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8 // indirect
diff --git a/go.sum b/go.sum
index 1837262..03d5288 100644
--- a/go.sum
+++ b/go.sum
@@ -75,6 +75,7 @@ github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1m
 github.com/envoyproxy/go-control-plane v0.9.7/go.mod h1:cwu0lG7PUMfa9snN8LXBig5ynNVH9qI8YYLbd1fK2po=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
+github.com/evanphx/json-patch v4.12.0+incompatible h1:4onqiflcdA9EOZ4RxV643DvftH5pOlLGNtQ5lPWQu84=
 github.com/evanphx/json-patch v4.12.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
 github.com/form3tech-oss/jwt-go v3.2.2+incompatible/go.mod h1:pbq4aXjuKjdthFRnoDwaVPLA+WlJuPGy+QneDUgJi2k=
 github.com/form3tech-oss/jwt-go v3.2.3+incompatible/go.mod h1:pbq4aXjuKjdthFRnoDwaVPLA+WlJuPGy+QneDUgJi2k=
@@ -225,6 +226,7 @@ github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7J
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
diff --git a/logs/stream.go b/logs/stream.go
index 237e553..54adeb1 100644
--- a/logs/stream.go
+++ b/logs/stream.go
@@ -8,7 +8,6 @@ import (
 	"sync"
 
 	corev1 "k8s.io/api/core/v1"
-	"k8s.io/client-go/kubernetes"
 )
 
 // concurrentWriter implements io.Writer.
@@ -33,13 +32,13 @@ func (cw *concurrentWriter) Write(p []byte) (int, error) {
 
 // Stream represents the logstream from an individual pod.
 type Stream struct {
-	clientset *kubernetes.Clientset
+	clientset KubernetesClient
 	pod       *corev1.Pod
 	dst       io.Writer
 }
 
 // NewStream initializes a new Stream.
-func NewStream(clientset *kubernetes.Clientset, pod *corev1.Pod, w io.Writer) *Stream {
+func NewStream(clientset KubernetesClient, pod *corev1.Pod, w io.Writer) *Stream {
 	return &Stream{
 		clientset: clientset,
 		pod:       pod,
diff --git a/logs/stream_test.go b/logs/stream_test.go
new file mode 100644
index 0000000..62f6478
--- /dev/null
+++ b/logs/stream_test.go
@@ -0,0 +1,26 @@
+package logs_test
+
+import (
+	"bytes"
+	"context"
+	"testing"
+
+	"git.netflux.io/rob/kubectl-persistent-logger/logs"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	testclient "k8s.io/client-go/kubernetes/fake"
+)
+
+func TestStream(t *testing.T) {
+	client := logs.KubernetesClient{Interface: testclient.NewSimpleClientset()}
+
+	var buf bytes.Buffer
+	pod := corev1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "foo", Namespace: "default"}}
+	stream := logs.NewStream(client, &pod, &buf)
+
+	err := stream.Copy(context.Background())
+	require.NoError(t, err)
+	assert.Equal(t, "[foo] fake logs\n", buf.String())
+}
diff --git a/logs/watcher.go b/logs/watcher.go
index 9500bc3..7f24b4f 100644
--- a/logs/watcher.go
+++ b/logs/watcher.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"io"
 	"log"
-	"os"
 	"time"
 
 	corev1 "k8s.io/api/core/v1"
@@ -14,28 +13,34 @@ import (
 	"k8s.io/client-go/kubernetes"
 )
 
+type KubernetesClient struct {
+	kubernetes.Interface
+}
+
 // Watcher watches a deployment and tails the logs for its currently active
 // pods.
 type Watcher struct {
 	deployName string
-	clientset  *kubernetes.Clientset
+	clientset  KubernetesClient
 	spec       map[string]*corev1.Pod
 	status     map[string]*Stream
+	dst        io.Writer
 }
 
 // NewWatcher creates a new Watcher.
-func NewWatcher(deployName string, clientset *kubernetes.Clientset) *Watcher {
+func NewWatcher(deployName string, clientset KubernetesClient, dst io.Writer) *Watcher {
 	return &Watcher{
 		deployName: deployName,
 		clientset:  clientset,
 		spec:       make(map[string]*corev1.Pod),
 		status:     make(map[string]*Stream),
+		dst:        dst,
 	}
 }
 
 // Watch watches a deployment.
 func (w *Watcher) Watch(ctx context.Context) error {
-	dst := NewConcurrentWriter(os.Stdout)
+	dst := NewConcurrentWriter(w.dst)
 
 	ticker := time.NewTicker(time.Second)
 	defer ticker.Stop()
@@ -65,6 +70,9 @@ func (w *Watcher) Watch(ctx context.Context) error {
 
 	for {
 		select {
+		case <-ctx.Done():
+			return ctx.Err()
+
 		case <-ticker.C:
 			// Iterate through the desired state (w.spec) and launch goroutines to
 			// process the logs of any missing pods.
diff --git a/logs/watcher_test.go b/logs/watcher_test.go
new file mode 100644
index 0000000..6d87d9f
--- /dev/null
+++ b/logs/watcher_test.go
@@ -0,0 +1,70 @@
+package logs_test
+
+import (
+	"bytes"
+	"context"
+	"testing"
+	"time"
+
+	"git.netflux.io/rob/kubectl-persistent-logger/logs"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/watch"
+	testclient "k8s.io/client-go/kubernetes/fake"
+	k8stest "k8s.io/client-go/testing"
+)
+
+func TestWatcher(t *testing.T) {
+	clientset := testclient.NewSimpleClientset(
+		&appsv1.Deployment{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "mydeployment",
+				Namespace: "default",
+			},
+			Spec: appsv1.DeploymentSpec{
+				Selector: &metav1.LabelSelector{
+					MatchLabels: map[string]string{"mylabelname": "mylabelvalue"},
+				},
+			},
+		},
+	)
+
+	k8swatcher := watch.NewFake()
+	clientset.PrependWatchReactor("pods", k8stest.DefaultWatchReactor(k8swatcher, nil))
+	pods := []*corev1.Pod{
+		{
+			ObjectMeta: metav1.ObjectMeta{Name: "foo", Namespace: "default"},
+			Status:     corev1.PodStatus{Phase: corev1.PodRunning},
+		},
+		{
+			ObjectMeta: metav1.ObjectMeta{Name: "bar", Namespace: "default"},
+			Status:     corev1.PodStatus{Phase: corev1.PodRunning},
+		},
+		{
+			ObjectMeta: metav1.ObjectMeta{Name: "baz", Namespace: "default"},
+			Status:     corev1.PodStatus{Phase: corev1.PodPending},
+		},
+	}
+
+	go func() {
+		defer k8swatcher.Stop()
+		for _, pod := range pods {
+			time.Sleep(time.Millisecond * 300)
+			k8swatcher.Add(pod)
+		}
+	}()
+
+	client := logs.KubernetesClient{Interface: clientset}
+
+	var buf bytes.Buffer
+	watcher := logs.NewWatcher("mydeployment", client, &buf)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	err := watcher.Watch(ctx)
+	require.EqualError(t, err, context.DeadlineExceeded.Error())
+	assert.Equal(t, "[foo] fake logs\n[bar] fake logs\n", buf.String())
+}
diff --git a/main.go b/main.go
index db15477..55c8a30 100644
--- a/main.go
+++ b/main.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"flag"
 	"log"
+	"os"
 	"path/filepath"
 
 	"git.netflux.io/rob/kubectl-persistent-logger/logs"
@@ -34,7 +35,7 @@ func main() {
 	}
 
 	ctx := context.Background()
-	watcher := logs.NewWatcher(*deployName, clientset)
+	watcher := logs.NewWatcher(*deployName, logs.KubernetesClient{Interface: clientset}, os.Stdout)
 	if err := watcher.Watch(ctx); err != nil {
 		log.Fatal(err)
 	}