PLT-6112: Add some more unit tests to the model package (#6142)

* Unit Tests for model/push_response.go

* Unit tests for security_bulletin.go

* Unit tests for webrtc.go

* Unit tests for model/password_recovery.go

* Add missing headers.

* Unit tests for model/license.go

* Tidy up existing tests.

* Simplify JSON to/from tests.

* Fix gofmt

model/push_response_test.go

@@ -0,0 +1,34 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestNewOkPushResponse(t *testing.T) {
+	r := NewOkPushResponse()
+	CheckString(t, r["status"], "OK")
+}
+
+func TestNewRemovePushResponse(t *testing.T) {
+	r := NewRemovePushResponse()
+	CheckString(t, r["status"], "REMOVE")
+}
+
+func TestNewErrorPushResponse(t *testing.T) {
+	r := NewErrorPushResponse("error message")
+	CheckString(t, r["status"], "FAIL")
+	CheckString(t, r["error"], "error message")
+}
+
+func TestPushResponseToFromJson(t *testing.T) {
+	r := NewErrorPushResponse("error message")
+	j := r.ToJson()
+	r1 := PushResponseFromJson(strings.NewReader(j))
+
+	CheckString(t, r1["status"], r["status"])
+	CheckString(t, r1["error"], r["error"])
+}