diff --git a/client_test.go b/client_test.go
new file mode 100644
index 0000000..8394936
--- /dev/null
+++ b/client_test.go
@@ -0,0 +1,52 @@
+package asynq
+
+import (
+	"testing"
+	"time"
+)
+
+func TestClient(t *testing.T) {
+	r := setup(t)
+	client := &Client{rdb: r}
+
+	tests := []struct {
+		task              *Task
+		processAt         time.Time
+		wantQueueSize     int64
+		wantScheduledSize int64
+	}{
+		{
+			task:              &Task{Type: "send_email", Payload: map[string]interface{}{"to": "customer@gmail.com", "from": "merchant@example.com"}},
+			processAt:         time.Now(),
+			wantQueueSize:     1,
+			wantScheduledSize: 0,
+		},
+		{
+			task:              &Task{Type: "send_email", Payload: map[string]interface{}{"to": "customer@gmail.com", "from": "merchant@example.com"}},
+			processAt:         time.Now().Add(2 * time.Hour),
+			wantQueueSize:     0,
+			wantScheduledSize: 1,
+		},
+	}
+
+	for _, tc := range tests {
+		// clean up db before each test case.
+		if err := r.client.FlushDB().Err(); err != nil {
+			t.Fatal(err)
+		}
+
+		err := client.Process(tc.task, tc.processAt)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if l := r.client.LLen(defaultQueue).Val(); l != tc.wantQueueSize {
+			t.Errorf("%q has length %d, want %d", defaultQueue, l, tc.wantQueueSize)
+		}
+
+		if l := r.client.ZCard(scheduled).Val(); l != tc.wantScheduledSize {
+			t.Errorf("%q has length %d, want %d", scheduled, l, tc.wantScheduledSize)
+		}
+	}
+}