diff --git a/src/github.com/matrix-org/dendrite/typingserver/cache/cache.go b/src/github.com/matrix-org/dendrite/typingserver/cache/cache.go
index fcf32211a..76e460fdc 100644
--- a/src/github.com/matrix-org/dendrite/typingserver/cache/cache.go
+++ b/src/github.com/matrix-org/dendrite/typingserver/cache/cache.go
@@ -18,11 +18,11 @@ import (
 )
 
 var (
-	userExists           = struct{}{} // Value denoting user is present in a userSet
+	userExists           = struct{}{} // Value denoting user is present in a userSet.
 	defaultTypingTimeout = 10 * time.Second
 )
 
-// userSet is a map of user IDs
+// userSet is a map of user IDs.
 type userSet map[string]struct{}
 
 // TypingCache maintains a list of users typing in each room.
diff --git a/src/github.com/matrix-org/dendrite/typingserver/cache/cache_test.go b/src/github.com/matrix-org/dendrite/typingserver/cache/cache_test.go
new file mode 100644
index 000000000..b8118061c
--- /dev/null
+++ b/src/github.com/matrix-org/dendrite/typingserver/cache/cache_test.go
@@ -0,0 +1,97 @@
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	"reflect"
+	"sort"
+	"testing"
+	"time"
+)
+
+const defaultInterval = time.Second
+
+func TestTypingCache(t *testing.T) {
+	tCache := NewTypingCache()
+	if tCache == nil {
+		t.Fatal("NewTypingCache failed")
+	}
+
+	t.Run("AddTypingUser", func(t *testing.T) {
+		testAddTypingUser(t, tCache)
+	})
+
+	t.Run("GetTypingUsers", func(t *testing.T) {
+		testGetTypingUsers(t, tCache)
+	})
+
+	t.Run("GetTypingUsersAfterTimeout", func(t *testing.T) {
+		testGetTypingUsersAfterTimeout(t, tCache)
+	})
+}
+
+func testAddTypingUser(t *testing.T, tCache *TypingCache) {
+	timeAfterDefaultInterval := time.Now().Add(defaultInterval)
+	timeAfterTwiceDefaultInterval := time.Now().Add(2 * defaultInterval)
+	tests := []struct {
+		userID string
+		roomID string
+		expire *time.Time
+	}{
+		{"user1", "room1", nil},
+		{"user2", "room1", nil},
+		{"user3", "room1", nil},
+		{"user4", "room1", nil},
+		{"user1", "room2", &timeAfterDefaultInterval},
+		{"user1", "room2", &timeAfterTwiceDefaultInterval},
+	}
+
+	for _, tt := range tests {
+		tCache.AddTypingUser(tt.userID, tt.roomID, tt.expire)
+	}
+}
+
+func testGetTypingUsers(t *testing.T, tCache *TypingCache) {
+	tests := []struct {
+		roomID    string
+		wantUsers []string
+	}{
+		{"room1", []string{"user1", "user2", "user3", "user4"}},
+		{"room2", []string{"user1"}},
+	}
+
+	for _, tt := range tests {
+		gotUsers := tCache.GetTypingUsers(tt.roomID)
+		sort.Strings(gotUsers)
+		sort.Strings(tt.wantUsers)
+		if !reflect.DeepEqual(gotUsers, tt.wantUsers) {
+			t.Errorf("TypingCache.GetTypingUsers(%s) = %v, want %v", tt.roomID, gotUsers, tt.wantUsers)
+		}
+	}
+}
+
+func testGetTypingUsersAfterTimeout(t *testing.T, tCache *TypingCache) {
+	time.Sleep(defaultInterval)
+	tests := []struct {
+		roomID    string
+		wantUsers []string
+	}{
+		{"room2", []string{"user1"}},
+	}
+
+	for _, tt := range tests {
+		if gotUsers := tCache.GetTypingUsers(tt.roomID); !reflect.DeepEqual(gotUsers, tt.wantUsers) {
+			t.Errorf("TypingCache.GetTypingUsers(%s) = %v, want %v", tt.roomID, gotUsers, tt.wantUsers)
+		}
+	}
+}