diff --git a/User.go b/User.go
index e7d3603..a23b92c 100644
--- a/User.go
+++ b/User.go
@@ -137,7 +137,7 @@ func (u User) GetShortName() string {
 	if len(supn) != 2 {
 		return u.UserPrincipalName
 	}
-	return strings.ToUpper(supn[0])
+	return supn[0]
 }
 
 // GetFullName returns the full name in that format: <firstname> <lastname>
@@ -145,6 +145,11 @@ func (u User) GetFullName() string {
 	return fmt.Sprintf("%v %v", u.GivenName, u.Surname)
 }
 
+// PrettySimpleString returns the User-instance simply formatted for logging purposes: {FullName (email) (activePhone)}
+func (u User) PrettySimpleString() string {
+	return fmt.Sprintf("{ %v (%v) (%v) }", u.GetFullName(), u.Mail, u.GetActivePhone())
+}
+
 // UpdateUser patches this user object. Note, only set the fields that should be changed.
 //
 // IMPORTANT: the user cannot be disabled (field AccountEnabled) this way, because the
@@ -208,11 +213,6 @@ func (u User) DeleteUser(opts ...DeleteQueryOption) error {
 	return err
 }
 
-// PrettySimpleString returns the User-instance simply formatted for logging purposes: {FullName (email) (activePhone)}
-func (u User) PrettySimpleString() string {
-	return fmt.Sprintf("{ %v (%v) (%v) }", u.GetFullName(), u.Mail, u.GetActivePhone())
-}
-
 // Equal returns wether the user equals the other User by comparing every property
 // of the user including the ID
 func (u User) Equal(other User) bool {
diff --git a/User_test.go b/User_test.go
index 73c2f19..e13b1fb 100644
--- a/User_test.go
+++ b/User_test.go
@@ -53,6 +53,13 @@ func TestUser_ListCalendars(t *testing.T) {
 	if skipCalendarTests {
 		t.Skip("Skipping due to missing 'MSGraphExistingCalendarsOfUser' value")
 	}
+	// testing for ErrNotGraphClientSourced
+	notGraphClientSourcedUser := User{ID: "none"}
+	_, err := notGraphClientSourcedUser.ListCalendars()
+	if err != ErrNotGraphClientSourced {
+		t.Errorf("Expected error \"ErrNotGraphClientSourced\", but got: %v", err)
+	}
+	// continue with normal tests
 	userToTest := GetTestUser(t)
 
 	var wantedCalendars []Calendar
@@ -160,6 +167,14 @@ func TestUser_String(t *testing.T) {
 }
 
 func TestUser_UpdateUser(t *testing.T) {
+	// testing for ErrNotGraphClientSourced
+	notGraphClientSourcedUser := User{ID: "none"}
+	err := notGraphClientSourcedUser.UpdateUser(User{})
+	if err != ErrNotGraphClientSourced {
+		t.Errorf("Expected error \"ErrNotGraphClientSourced\", but got: %v", err)
+	}
+
+	// continue with normal tests
 	testuser := createUnitTestUser(t)
 
 	targetedCompanyName := "go-msgraph unit test suite UpdateUser" + randomString(25)
@@ -178,3 +193,32 @@ func TestUser_UpdateUser(t *testing.T) {
 		t.Errorf("Could not User.DeleteUser() (for %v) after User.UpdateUser tests: %v", testuser, err)
 	}
 }
+
+func TestUser_GetShortName(t *testing.T) {
+	// test a normal case
+	testuser := User{UserPrincipalName: "dumpty@contoso.com"}
+	if testuser.GetShortName() != "dumpty" {
+		t.Errorf("user.GetShortName() should return \"dumpty\", but returns: %v", testuser.GetShortName())
+	}
+	// test a case that actually should never happen... but we all know murphy
+	testuser = User{UserPrincipalName: "alice"}
+	if testuser.GetShortName() != "alice" {
+		t.Errorf("user.GetShortName() should return \"alice\", but returns: %v", testuser.GetShortName())
+	}
+}
+
+func TestUser_GetFullName(t *testing.T) {
+	testuser := User{GivenName: "Bob", Surname: "Rabbit"}
+	wanted := fmt.Sprintf("%v %v", testuser.GivenName, testuser.Surname)
+	if testuser.GetFullName() != wanted {
+		t.Errorf("user.GetFullName() should return \"%v\", but returns: \"%v\"", wanted, testuser.GetFullName())
+	}
+}
+
+func TestUser_PrettySimpleString(t *testing.T) {
+	testuser := User{GivenName: "Bob", Surname: "Rabbit", Mail: "bob.rabbit@contoso.com", MobilePhone: "+1 23456789"}
+	wanted := fmt.Sprintf("{ %v (%v) (%v) }", testuser.GetFullName(), testuser.Mail, testuser.GetActivePhone())
+	if testuser.PrettySimpleString() != wanted {
+		t.Errorf("user.GetFullName() should return \"%v\", but returns: \"%v\"", wanted, testuser.PrettySimpleString())
+	}
+}
diff --git a/docs/example_User.md b/docs/example_User.md
index 86a33d5..a2f42e2 100644
--- a/docs/example_User.md
+++ b/docs/example_User.md
@@ -45,4 +45,8 @@ err := user.UpdateUser(msgraph.User{DisplayName: "Rabbit 2.0"}, msgraph.UpdateWi
 
 // disable acccount
 err := user.DisableAccount()
+// enable user account again
+err := user.UpdateUser(User{AccountEnabled: true})
+// delete a user, use with caution!
+err := user.DeleteUser()
 ````
\ No newline at end of file